title: Annexin A2 regulates a disintegrin and metalloproteinase 17-mediated ectodomain shedding of pro-tumor necrosis factor-α in monocytes and colon epithelial cells.
abstract: BACKGROUND
  Understanding the mechanism of tumor necrosis factor (TNF)-α shedding is important because TNF-α triggers inflammatory bowel disease development. A disintegrin and metalloproteinase (ADAM) 17 is a key enzyme for the shedding of not only the type 1 membrane-anchored protein, amphiregulin, but also the type 2 protein, TNF-α. However, the detailed mechanism by which ADAM17 cleaves type 1 and 2 membrane-anchored proteins is unclear. Annexin (ANX) A2 is involved in ADAM17-mediated amphiregulin shedding. In this study, we examined whether ANX A2 is involved in TNF-α shedding.
  
  
  METHODS
  We prepared U937, HT29, and HCT116 cells overexpressing alkaline phosphatase (AP)-tagged proTNF-α and depleted ADAM17 and ANX A2. We assessed TNF-α release and shedding by measuring the TNF-α release concentration and AP activities in conditioned media after interleukin-1β or 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulation by enzyme-linked immunosorbent assay and AP assay, respectively. A direct association of ANX A2 with ADAM17 was examined with immunoprecipitation and Western blotting.
  
  
  RESULTS
  Enzyme-linked immunosorbent assay and AP assay showed interleukin-1β-induced TNF-α shedding in HCT116 and HT29 cells and TPA-induced TNF-α release in U937 cells. KB-R7785 and ADAM17 depletion significantly blocked TNF-α shedding by TPA. ANX A2 depletion significantly inhibited TNF-α shedding by interleukin-1β and TPA. In contrast, ANX A2 depletion did not abrogate ADAM17-mediated amphiregulin and heparin-binding epidermal growth factor-like growth factor shedding. ANX A2 was directly associated with ADAM17.
  
  
  CONCLUSIONS
  ANX A2 was closely associated with ADAM17 and played an important role in TNF-α shedding by TPA. Inhibition of ANX A2 might be a new therapeutic strategy for prevention of TNF-α shedding during inflammatory bowel disease inflammation.
authors.affiliation: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Tsukamoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanida
authors.forename: Keiji
authors.initials: K
authors.lastname: Ozeki
authors.forename: Masahide
authors.initials: M
authors.lastname: Ebi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Mizoshita
authors.forename: Takaya
authors.initials: T
authors.lastname: Shimura
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Mori
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kataoka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kamiya
authors.forename: Shinji
authors.initials: S
authors.lastname: Fukuda
authors.forename: Shigeki
authors.initials: S
authors.lastname: Higashiyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Joh
mesh_terms: D051722:ADAM Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000072198:ADAM17 Protein; D017306:Annexin A2 / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002273:Carcinogens / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D047468:Immunoprecipitation; D053583:Interleukin-1beta / Q000494:pharmacology; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D017306:Annexin A2; D002273:Carcinogens; D053583:Interleukin-1beta; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D013755:Tetradecanoylphorbol Acetate