title: Defects in NADPH Oxidase GenesNOX1andDUOX2in Very Early Onset Inflammatory Bowel Disease.
abstract: OBJECTIVE
  Defects in intestinal innate defense systems predispose patients to inflammatory bowel disease (IBD). Reactive oxygen species (ROS) generated by nicotinamide-adenine dinucleotide phosphate (NADPH) oxidases in the mucosal barrier maintain gut homeostasis and defend against pathogenic attack. We hypothesized that molecular genetic defects in intestinal NADPH oxidases might be present in children with IBD.
  
  
  METHODS
  After targeted exome sequencing of epithelial NADPH oxidasesNOX1andDUOX2on 209 children with very early onset inflammatory bowel disease (VEOIBD), the identified mutations were validated using Sanger Sequencing. A structural analysis ofNOX1andDUOX2variants was performed by homology in silico modeling. The functional characterization included ROS generation in model cell lines and in in vivo transduced murine crypts, protein expression, intracellular localization, and cell-based infection studies with the enteric pathogensCampylobacter jejuniand enteropathogenicEscherichia coli.
  
  
  RESULTS
  We identified missense mutations inNOX1(c.988G>A, p.Pro330Ser; c.967G>A, p.Asp360Asn) andDUOX2(c.4474G>A, p.Arg1211Cys; c.3631C>T, p.Arg1492Cys) in 5 of 209 VEOIBD patients. TheNOX1p.Asp360Asn variant was replicated in a male Ashkenazi Jewish ulcerative colitis cohort. AllNOX1andDUOX2variants showed reduced ROS production compared with wild-type enzymes. Despite appropriate cellular localization and comparable pathogen-stimulated translocation of altered oxidases, cells harboringNOX1orDUOX2variants had defective host resistance to infection withC. jejuni.
  
  
  CONCLUSIONS
  This study identifies the first inactivating missense variants inNOX1andDUOX2associated with VEOIBD. Defective ROS production from intestinal epithelial cells constitutes a risk factor for developing VEOIBD.
authors: Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland.
authors: Patti
authors: P
authors: Hayes
authors: SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada ; Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Sandeep
authors: S
authors: Dhillon
authors: Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland.
authors: Kim
authors: K
authors: O'Neill
authors: SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada ; Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Cornelia
authors: C
authors: Thoeni
authors: Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut.
authors: Ken Y
authors: KY
authors: Hui
authors: SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada ; Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Abdul
authors: A
authors: Elkadri
authors: SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada ; Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Conghui H
authors: CH
authors: Guo
authors: Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland.
authors: Lidija
authors: L
authors: Kovacic
authors: Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland.
authors: Gabriella
authors: G
authors: Aviello
authors: National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland.
authors: Luis A
authors: LA
authors: Alvarez
authors: Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Anne M
authors: AM
authors: Griffiths
authors: Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Children's Hospital Boston; Division of Gastroenterology and Hepatology, Brigham & Women's Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts.
authors: Scott B
authors: SB
authors: Snapper
authors: Harvey M. and Lyn P. Meyerhoff Inflammatory Bowel Disease Center, Department of Medicine, School of Medicine and the Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.
authors: Steven R
authors: SR
authors: Brant
authors: National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors: James H
authors: JH
authors: Doroshow
authors: Mount Sinai Hospital Inflammatory Bowel Disease Group, University of Toronto, Zane Cohen Centre for Digestive Diseases, Toronto, Ontario, Canada.
authors: Mark S
authors: MS
authors: Silverberg
authors: Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York.
authors: Inga
authors: I
authors: Peter
authors: F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California.
authors: Dermot P B
authors: DP
authors: McGovern
authors: Section of Gastroenterology, Department of Internal Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.
authors: Judy
authors: J
authors: Cho
authors: SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: John H
authors: JH
authors: Brumell
authors: Translational Gastroenterology Unit, Nuffield Department of Clinical Medicine and Children's Hospital, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom.
authors: Holm H
authors: HH
authors: Uhlig
authors: Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland ; National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland.
authors: Billy
authors: B
authors: Bourke
authors: SickKids Inflammatory Bowel Disease Center and Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada ; Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Aleixo A
authors: AA
authors: Muise
authors: Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland ; National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland.
authors: Ulla G
authors: UG
authors: Knaus
keywords: DUOX2; Inflammatory Bowel Disease; NADPH Oxidase; NOX1; Reactive Oxygen Species; VEOIBD