title: Induction of endothelial cell apoptosis by the binding of anti-endothelial cell antibodies to Hsp60 in vasculitis-associated systemic autoimmune diseases.
abstract: OBJECTIVE
  Anti-endothelial cell antibodies (AECAs), which recognize a number of endothelial antigens, are seen in patients with systemic autoimmune diseases, more often in the presence of vasculitis than in its absence. Some AECAs induce apoptosis of endothelial cells (ECs), but their target antigens remain unknown. The aim of this study was to determine whether Hsp60 is a target antigen and whether AECAs induce apoptosis in ECs.
  
  
  METHODS
  Two-dimensional electrophoresis and conventional Western blotting techniques were used to characterize AECA targets. Hsp60 reactivity was determined by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Hsp60 was shown to be targeted by a proportion of AECAs. The level of reactivity was higher in patients with systemic autoimmune disease and vasculitis than in those without vasculitis and in patients with systemic lupus erythematosus than in patients with other systemic autoimmune diseases. Hsp60 was expressed on the plasma membrane of heat-stressed ECs, and this followed Hsp60 messenger RNA transcription, confinement of the protein to the cytoplasm, and translocation of the protein to the surface. Shedding of Hsp60 from ECs was induced by stress and resulted in the binding of soluble Hsp60 to the surface of ECs, particularly stressed ECs. Apoptosis of ECs was triggered by anti-Hsp60-containing AECA-positive sera and was inhibited by preincubation of the ECs with recombinant Hsp60.
  
  
  CONCLUSIONS
  Our data support the notion that Hsp60 is an important target for AECAs and that such an interaction contributes to pathogenic effects, especially in vasculitis-associated systemic autoimmune disease.
authors.affiliation: Brest University Medical School, Brest, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Jamin
authors.forename: Christophe
authors.initials: C
authors.lastname: Dugué
authors.forename: Jean-Eric
authors.initials: JE
authors.lastname: Alard
authors.forename: Sandrine
authors.initials: S
authors.lastname: Jousse
authors.forename: Alain
authors.initials: A
authors.lastname: Saraux
authors.forename: Loïc
authors.initials: L
authors.lastname: Guillevin
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Piette
authors.forename: Pierre
authors.initials: P
authors.lastname: Youinou
mesh_terms: D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D017209:Apoptosis / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D018834:Chaperonin 60 / Q000737:chemistry / Q000276:immunology*; D004730:Endothelium, Vascular / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology; D008875:Middle Aged; D008969:Molecular Sequence Data; D014657:Vasculitis / Q000276:immunology* / Q000473:pathology
chemical_list: D001323:Autoantibodies; D018834:Chaperonin 60; D008565:Membrane Proteins