title: High Smad7 sustains inflammatory cytokine response in refractory coeliac disease.
abstract: Refractory coeliac disease (RCD) is a form of coeliac disease (CD) resistant to gluten-free diet and associated with elevated risk of complications. Many effector cytokines over-produced in the gut of patients with RCD are supposed to amplify the tissue-destructive immune response, but it remains unclear if the RCD-associated mucosal inflammation is sustained by defects in counter-regulatory mechanisms. The aim of the present study was to determine whether RCD-related inflammation is marked by high Smad7, an intracellular inhibitor of transforming growth factor-β1(TGF-β1) activity. Smad7 was evaluated in duodenal biopsy samples of patients with RCD, patients with active CD, patients with inactive CD and healthy controls by Western blotting, immunohistochemistry and real-time PCR. In the same samples, TGF-β1and phosphorylated (p)-Smad2/3 were evaluated by ELISA and immunohistochemistry, respectively. Pro-inflammatory cytokine expression was evaluated in RCD samples cultured with Smad7 sense or antisense oligonucleotide. Smad7 protein, but not RNA, expression was increased in RCD compared with active and inactive CD patients and healthy controls and this was associated with defective TGF-β1signalling, as marked by diminished p-Smad2/3 expression. TGF-β1protein content did not differ among groups. Knockdown of Smad7 in RCD biopsy samples reduced interleukin-6 and tumour necrosis factor-α expression. In conclusion, in RCD, high Smad7 associates with defective TGF-β1signalling and sustains inflammatory cytokine production. These results indicate a novel mechanism by which the mucosal cytokine response is amplified in RCD and suggest that targeting Smad7 can be therapeutically useful in RCD.
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Sedda
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Veronica
authors.initials: V
authors.lastname: De Simone
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Marafini
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Gerolamo
authors.initials: G
authors.lastname: Bevivino
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Izzo
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Omero Alessandro
authors.initials: OA
authors.lastname: Paoluzi
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Colantoni
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Ortenzi
authors.affiliation: First Department of Internal Medicine, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Giuffrida
authors.affiliation: First Department of Internal Medicine, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy.
authors.forename: Gino R
authors.initials: GR
authors.lastname: Corazza
authors.affiliation: Department of Molecular Medicine, San Matteo Hospital, University of Pavia, Pavia, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vanoli
authors.affiliation: First Department of Internal Medicine, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Di Sabatino
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pallone
authors.affiliation: Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Monteleone
mesh_terms: D001706:Biopsy; D002446:Celiac Disease / Q000276:immunology* / Q000628:therapy; D055050:Diet, Gluten-Free; D004386:Duodenum / Q000276:immunology*; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D015850:Interleukin-6 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000276:immunology*; D058990:Molecular Targeted Therapy; D034741:RNA, Small Interfering / Q000235:genetics; D012008:Recurrence; D015398:Signal Transduction; D051906:Smad7 Protein / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015850:Interleukin-6; D034741:RNA, Small Interfering; C497806:SMAD7 protein, human; D051906:Smad7 Protein; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha
keywords: gluten; inflammation; mucosal immune response; transforming growth factor-β