title: NOX2, p22phox and p47phox are targeted to the nuclear pore complex in ischemic cardiomyocytes colocalizing with local reactive oxygen species.
abstract: BACKGROUND
  NADPH oxidases play an essential role in reactive oxygen species (ROS)-based signaling in the heart. Previously, we have demonstrated that (peri)nuclear expression of the catalytic NADPH oxidase subunit NOX2 in stressed cardiomyocytes, e.g. under ischemia or high concentrations of homocysteine, is an important step in the induction of apoptosis in these cells. Here this ischemia-induced nuclear targeting and activation of NOX2 was specified in cardiomyocytes.
  
  
  METHODS
  The effect of ischemia, mimicked by metabolic inhibition, on nuclear localization of NOX2 and the NADPH oxidase subunits p22(phox) and p47(phox), was analyzed in rat neonatal cardiomyoblasts (H9c2 cells) using Western blot, immuno-electron microscopy and digital-imaging microscopy.
  
  
  RESULTS
  NOX2 expression significantly increased in nuclear fractions of ischemic H9c2 cells. In addition, in these cells NOX2 was found to colocalize in the nuclear envelope with nuclear pore complexes, p22(phox), p47(phox) and nitrotyrosine residues, a marker for the generation of ROS. Inhibition of NADPH oxidase activity, with apocynin and DPI, significantly reduced (peri)nuclear expression of nitrotyrosine.
  
  
  CONCLUSIONS
  We for the first time show that NOX2, p22(phox) and p47(phox) are targeted to and produce ROS at the nuclear pore complex in ischemic cardiomyocytes.
authors.affiliation: Department of Pathology, VU University Medical Centre, De Boelelaan 1117, Amsterdam, The Netherlands. n.hahn@vumc.nl
authors.forename: Nynke E
authors.initials: NE
authors.lastname: Hahn
authors.forename: Christof
authors.initials: C
authors.lastname: Meischl
authors.forename: Paul J M
authors.initials: PJ
authors.lastname: Wijnker
authors.forename: Rene J P
authors.initials: RJ
authors.lastname: Musters
authors.forename: Maarten
authors.initials: M
authors.lastname: Fornerod
authors.forename: Hans W R M
authors.initials: HW
authors.lastname: Janssen
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Paulus
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
authors.forename: Hans W M
authors.initials: HW
authors.lastname: Niessen
authors.forename: Paul A J
authors.initials: PA
authors.lastname: Krijnen
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D007511:Ischemia / Q000139:chemically induced / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D022022:Nuclear Pore / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D009861:Onium Compounds / Q000494:pharmacology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D012966:Sodium Cyanide / Q000009:adverse effects; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000098:Acetophenones; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D009861:Onium Compounds; D017382:Reactive Oxygen Species; C002744:3-nitrotyrosine; D014443:Tyrosine; C007517:diphenyleneiodonium; C056165:acetovanillone; C500593:Cybb protein, rat; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C515768:Cyba protein, rat; C060505:neutrophil cytosolic factor 1; D012966:Sodium Cyanide