title: Genomic ATG16L1 risk allele-restricted Paneth cell ER stress in quiescent Crohn's disease.
abstract: OBJECTIVE
  Although genome wide association studies have partly uncovered the genetic basis of Crohn's disease (CD), it remains a challenge to link genetic polymorphisms to functional intestinal phenotypes. Paneth cells are specialised antimicrobial epithelial cells localised to the small-intestinal crypt-base. Here, we investigate whether genomic variations in ATG16L1 affect Paneth cell function.
  
  
  METHODS
  Genomic variation of ATG16L1 (T300A, rs2241880) was determined in DNA from 78 patients with CD and 12 healthy controls. Paraffin-embedded ileal biopsies from patients with genotype AA (n=17), GA (n=38) and patients with the GG allele (n=23) were stained for GRP78, phospho-EIF2α, lysozyme, cleaved-caspase 3, phosphohistone H3, phospho-IκB, p65, phospho-p38MAPK and PHLDA1. Microbial composition of biopsies was assessed by PCR. Disease phenotype was scored.
  
  
  RESULTS
  In patients with quiescent disease but with an ATG16L1 risk allele, the endoplasmic reticulum (ER) stress markers GRP78 and pEIF2α were highly expressed in Paneth cells. Other CD risk gene variations did not correlate with Paneth cell ER stress. Functionally, patients with ER-stressed Paneth cells showed no changes in intestinal epithelial cells proliferation or apoptosis, Paneth cell or stem cell numbers, p65, phospho-IκB and phospho-p38 staining. However, a significantly increased presence of adherent-invasive Escherichia coli was observed in biopsies from patients with ER-stressed Paneth cells. Phenotypically, patients with GRP78 positive Paneth cells have relatively less colonic disease over ileal disease (-21%, p=0.04), more fistulas (+21%, p=0.05) and an increased need for intestinal surgery (+38%, p=0.002).
  
  
  CONCLUSIONS
  The ATG16L1 T300A polymorphism defines a specific subtype of patients with CD, characterised by Paneth cell ER stress even during quiescent disease. Paneth cell ER stress correlates with bacterial persistence, and is thus likely to modulate antimicrobial functionality of this cell type in patients with CD.
authors: Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: J Jasper
authors: JJ
authors: Deuring
authors: Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Gwenny M
authors: GM
authors: Fuhler
authors: Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Sergey R
authors: SR
authors: Konstantinov
authors: Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Maikel P
authors: MP
authors: Peppelenbosch
authors: Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Ernst J
authors: EJ
authors: Kuipers
authors: Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: Colin
authors: C
authors: de Haar
authors: Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors: C Janneke
authors: CJ
authors: van der Woude
mesh_terms: D000071183:Autophagy-Related Proteins; D001706:Biopsy; D002352:Carrier Proteins / Q000235:genetics*; D016022:Case-Control Studies; D002478:Cells, Cultured; D003424:Crohn Disease / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D004269:DNA, Bacterial / Q000032:analysis; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000235:genetics* / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D060005:Genotyping Techniques; D006801:Humans; D007082:Ileum / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D064307:Microbiota; D015999:Multivariate Analysis; D019879:Paneth Cells / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors
chemical_list: C518959:ATG16L1 protein, human; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D000091342:Endoplasmic Reticulum Chaperone BiP; D005819:Genetic Markers; C000717247:HSPA5 protein, human
keywords: CROHN'S DISEASE; IBD - GENETICS; IBD BASIC RESEARCH; SMALL BOWEL DISEASE; SMALL INTESTINAL BIOPSY