title: Crohn's Disease Fibroblasts Overproduce the Novel Protein KIAA1199 to Create Proinflammatory Hyaluronan Fragments.
abstract: OBJECTIVE
  Crohn's Disease (CD) is a chronic inflammatory disease of the gastrointestinal tract. Fibrosis, a serious complication of CD, occurs when activated intestinal fibroblasts deposit excessive amounts of extracellular matrix (ECM) in affected areas. A major component of the ECM is high-molecular-weight hyaluronan (HA) that, when depolymerized to low-molecular-weight fragments, becomes proinflammatory and profibrotic. Mechanisms for HA degradation are incompletely understood, but the novel protein KIAA1199 recently was discovered to degrade HA. We hypothesized that KIAA1199 protein is increased in CD colon fibroblasts and generates HA fragments that foster inflammation and fibrosis.
  
  
  METHODS
  Fibroblasts were isolated from explants of surgically resected colon tissue from CD and non-inflammatory bowel disease control (ND) patients. Protein levels and tissue distribution of KIAA1199 were assessed by immunoblot and immunostaining, and functional HA degradation was measured biochemically.
  
  
  RESULTS
  Increased levels of KIAA1199 protein were produced and deposited in the ECM by cultured CD fibroblasts compared with controls. Treatment of fibroblasts with the proinflammatory cytokine interleukin (IL) 6 increased deposition of KIAA1199 in the ECM. CD fibroblasts also produce significantly higher levels of IL6 compared with controls, and antibody blockade of IL6 receptors in CD colon fibroblasts decreased the level of KIAA1199 protein in the ECM. Colon fibroblasts degrade HA, however, small interfering RNA silencing of KIAA1199 abrogated that ability.
  
  
  CONCLUSIONS
  CD fibroblasts produce increased levels of KIAA1199 primarily through an IL6-driven autocrine mechanism. This leads to excessive degradation of HA and the generation of proinflammatory HA fragments, which contributes to maintenance of gut inflammation and fibrosis.
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Artin
authors.initials: A
authors.lastname: Soroosh
authors.affiliation: Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California.
authors.forename: Sami
authors.initials: S
authors.lastname: Albeiroti
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Gail A
authors.initials: GA
authors.lastname: West
authors.affiliation: Research Core Services, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Belinda
authors.initials: B
authors.lastname: Willard
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Claudio
authors.initials: C
authors.lastname: Fiocchi
authors.affiliation: Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio.
authors.forename: Carol A
authors.initials: CA
authors.lastname: de la Motte
keywords: CD, Crohn’s disease; Crohn’s Disease; DAMP, damage-associated molecular pattern; ECM, extracellular matrix; FBS, fetal bovine serum; Fibrosis; HA, hyaluronan; HBSS, Hank's balanced salt solution; HIF, human intestinal fibroblasts; HYAL, hyaluronidase; Hyaluronan; IBD, inflammatory bowel disease; IL, interleukin; IL6R, interleukin 6 receptor; KIAA1199; LC-MS, liquid chromatography–mass spectrometry; ND, non–inflammatory bowel disease control; NF-κB, nuclear factor-κB; PAGE, polyacrylamide gel electrophoresis; PBST, phosphate-buffered saline with 0.1% Tween-20; SDS, sodium dodecyl sulfate; TGF, transforming growth factor; TLR, Toll-like receptor; TNF, tumor necrosis factor; siRNA, small interfering RNA