title: The valosin-containing protein promotes cardiac survival through the inducible isoform of nitric oxide synthase.
abstract: OBJECTIVE
  Expression of the heat shock protein 22 (Hsp22) in the heart stimulates cardiac cell survival through activation of the Akt pathway and expression of the inducible nitric oxide (NO) synthase (iNOS), the mediator of ischaemic preconditioning and the most powerful prophylaxis against cardiac cell death. The goal of the present study was to elucidate the downstream effector by which Hsp22 and Akt increase iNOS expression. We tested both in vivo and in vitro the hypothesis that such an effector is the valosin-containing protein (VCP), an Akt substrate, which activates the transcription factor NF-κB, using a transgenic mouse with cardiac-specific over-expression of Hsp22, as well as isolated rat cardiac myocytes.
  
  
  RESULTS
  Using two-dimensional gel electrophoresis and mass spectrometry combined with immunoprecipitation, we found that Hsp22 and Akt co-localize and interact together with VCP. Adeno-mediated over-expression of VCP in isolated cardiac myocytes activated NF-κB and dose-dependently increased the expression of iNOS, which was abolished upon NF-κB inhibition. Over-expression of a dominant-negative (DN) mutant of VCP did not increase iNOS expression. VCP, but not its DN mutant, protected against chelerythrine-induced apoptosis, which was suppressed by inhibition of either NF-κB or iNOS. VCP-mediated activation of the NF-κB/iNOS pathway was also prevented upon inhibition of Akt.
  
  
  CONCLUSIONS
  We conclude that the Akt substrate, VCP, mediates the increased expression of iNOS downstream from Hsp22 through an NF-κB-dependent mechanism.
authors.affiliation: Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, 07103, USA.
authors.forename: Paulo
authors.initials: P
authors.lastname: Lizano
authors.forename: Eman
authors.initials: E
authors.lastname: Rashed
authors.forename: Hobin
authors.initials: H
authors.lastname: Kang
authors.forename: Huacheng
authors.initials: H
authors.lastname: Dai
authors.forename: Xiangzhen
authors.initials: X
authors.lastname: Sui
authors.forename: Lin
authors.initials: L
authors.lastname: Yan
authors.forename: Hongyu
authors.initials: H
authors.lastname: Qiu
authors.forename: Christophe
authors.initials: C
authors.lastname: Depre
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis / Q000502:physiology*; D000818:Animals; D018797:Cell Cycle Proteins / Q000032:analysis / Q000502:physiology*; D002470:Cell Survival; D002478:Cells, Cultured; D050886:HSP20 Heat-Shock Proteins / Q000502:physiology; D006360:Heat-Shock Proteins; D007527:Isoenzymes / Q000502:physiology; D008297:Male; D051379:Mice; D018832:Molecular Chaperones; D009124:Muscle Proteins / Q000502:physiology; D032383:Myocytes, Cardiac / Q000166:cytology / Q000502:physiology*; D016328:NF-kappa B / Q000502:physiology; D052247:Nitric Oxide Synthase Type II / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000074405:Valosin Containing Protein
chemical_list: D018797:Cell Cycle Proteins; D050886:HSP20 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C490206:Hspb8 protein, mouse; D007527:Isoenzymes; D018832:Molecular Chaperones; D009124:Muscle Proteins; D016328:NF-kappa B; D052247:Nitric Oxide Synthase Type II; D051057:Proto-Oncogene Proteins c-akt; D000251:Adenosine Triphosphatases; D000074405:Valosin Containing Protein; C000614179:Vcp protein, mouse; C000614180:Vcp protein, rat
keywords: H11 kinase; Ischaemia; Nitric oxide synthase; Preconditioning; Valosin-containing protein