title: Necroptosis is active in children with inflammatory bowel disease and contributes to heighten intestinal inflammation.
abstract: OBJECTIVE
  A new caspase-independent mode of programmed cell death, termed necroptosis, has recently been identified. Altered expression of molecules involved in the necroptosis pathway has been shown to trigger intestinal inflammation. The initiation of necroptosis is principally mediated by the release of receptor interacting protein 3 (RIP3) from suppression by caspase-8. Furthermore, it has been suggested that the mixed lineage kinase domain-like (MLKL) factor is an interacting target of RIP3 in active necroptosis. This study aims at investigating the occurrence of necroptosis in children with inflammatory bowel disease (IBD) and its contribution to human intestinal inflammation.
  
  
  METHODS
  Biopsy samples were collected from the ileum and colon of 33 children with Crohn's disease, 30 with ulcerative colitis, and 20 healthy controls. Ten children with allergic colitis (AC) were used as non-IBD comparators. RIP3, caspase-8, and MLKL protein expression levels were evaluated by western blotting. The adenocarcinoma cell line HT29 was used for in vitro experiments.
  
  
  RESULTS
  RIP3 and MLKL increased (P<0.01) in inflamed tissues of IBD and AC patients, whereas caspase-8 was reduced. No variations were observed in uninflamed tissues of patients. The relationship between RIP3 increase, active necroptosis, and intestinal inflammation was confirmed by in vitro analyses.
  
  
  CONCLUSIONS
  We show for the first time that necroptosis is strongly associated with intestinal inflammation in children with IBD and contributes to strengthen the inflammatory process. We believe that RIP3 and MLKL could represent attractive targets for the management of human IBD.
authors: Department of Radiobiology and Human Health, ENEA, Rome, Italy.
authors: Maria
authors: M
authors: Pierdomenico
authors: Department of Radiobiology and Human Health, ENEA, Rome, Italy.
authors: Anna
authors: A
authors: Negroni
authors: Department of Radiobiology and Human Health, ENEA, Rome, Italy.
authors: Laura
authors: L
authors: Stronati
authors: Department of Radiobiology and Human Health, ENEA, Rome, Italy.
authors: Roberta
authors: R
authors: Vitali
authors: Department of Radiobiology and Human Health, ENEA, Rome, Italy.
authors: Enrica
authors: E
authors: Prete
authors: Pattern Recognition Receptor Discovery Performance Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA.
authors: John
authors: J
authors: Bertin
authors: Pattern Recognition Receptor Discovery Performance Unit, GlaxoSmithKline, Collegeville, Pennsylvania, USA.
authors: Peter J
authors: PJ
authors: Gough
authors: Pediatric Gastroenterology and Liver Unit, Department of Pediatrics, Sapienza University of Rome, Rome, Italy.
authors: Marina
authors: M
authors: Aloi
authors: Pediatric Gastroenterology and Liver Unit, Department of Pediatrics, Sapienza University of Rome, Rome, Italy.
authors: Salvatore
authors: S
authors: Cucchiara
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001707:Biopsy, Needle; D015153:Blotting, Western; D053181:Caspase 8 / Q000378:metabolism*; D016923:Cell Death / Q000235:genetics*; D002470:Cell Survival; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D003106:Colon / Q000473:pathology; D003424:Crohn Disease / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007082:Ileum / Q000473:pathology; D007150:Immunohistochemistry; D015212:Inflammatory Bowel Diseases / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D011446:Prospective Studies; D011494:Protein Kinases / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000235:genetics*; D018570:Risk Assessment; D012720:Severity of Illness Index; D015398:Signal Transduction; D018709:Statistics, Nonparametric
chemical_list: C570693:MLKL protein, human; D011494:Protein Kinases; C119705:RIPK3 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D053181:Caspase 8