title: Endothelial cell-derived microparticles induce plasmacytoid dendritic cell maturation: potential implications in inflammatory diseases.
abstract: BACKGROUND
  Increased circulating endothelial microparticles, resulting from vascular endothelium dysfunction, and plasmacytoid dendritic cell activation are both encountered in common inflammatory disorders. The aim of our study was to determine whether interactions between endothelial microparticles and plasmacytoid dendritic cells could contribute to such pathologies.
  
  
  METHODS
  Microparticles generated from endothelial cell lines, platelets or activated T cells were incubated with human plasmacytoid dendritic cells sorted from healthy donor blood or with monocyte-derived dendritic cells. Dendritic cell maturation was evaluated by flow cytometry, cytokine secretion as well as naive T-cell activation and polarization. Labeled microparticles were also used to study cellular interactions.
  
  
  RESULTS
  Endothelial microparticles induced plasmacytoid dendritic cell maturation. In contrast, conventional dendritic cells were resistant to endothelial microparticle-induced maturation. In addition to upregulation of co-stimulatory molecules, endothelial microparticle-matured plasmacytoid dendritic cells secreted inflammatory cytokines (interleukins 6 and 8, but no interferon-alpha) and also induced allogeneic naive CD4(+) T cells to proliferate and to produce type 1 cytokines such as interferon-gamma and tumor necrosis factor-alpha. Endothelial microparticle endocytosis by plasmacytoid dendritic cells appeared to be required for plasmacytoid dendritic cell maturation. Importantly, the ability of endothelial microparticles to induce plasmacytoid dendritic cells to mature was specific as microparticles derived from activated T cells or platelets (the major source of circulating microparticules in healthy subjects) did not induce such plasmacytoid dendritic cell maturation.
  
  
  CONCLUSIONS
  Our data show that endothelial microparticles specifically induce plasmacytoid dendritic cell maturation and production of inflammatory cytokines. This novel activation pathway may be implicated in various inflammatory disorders and endothelial microparticles could be an important immunmodulatory therapeutic target.
authors: Inserm UMR645, University of Franche-Comté, EFS Bourgogne Franche-Comté, IFR133, Besançon, France.
authors: Fanny
authors: F
authors: Angelot
authors: Estelle
authors: E
authors: Seillès
authors: Sabeha
authors: S
authors: Biichlé
authors: Yael
authors: Y
authors: Berda
authors: Béatrice
authors: B
authors: Gaugler
authors: Joel
authors: J
authors: Plumas
authors: Laurence
authors: L
authors: Chaperot
authors: Françoise
authors: F
authors: Dignat-George
authors: Pierre
authors: P
authors: Tiberghien
authors: Philippe
authors: P
authors: Saas
authors: Francine
authors: F
authors: Garnache-Ottou
mesh_terms: D002454:Cell Differentiation / Q000276:immunology*; D002460:Cell Line; D055252:Cell-Derived Microparticles / Q000276:immunology* / Q000473:pathology; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D003713:Dendritic Cells / Q000473:pathology*; D042783:Endothelial Cells / Q000276:immunology / Q000473:pathology*; D004730:Endothelium, Vascular / Q000276:immunology / Q000473:pathology; D006801:Humans; D007249:Inflammation / Q000276:immunology
chemical_list: D016207:Cytokines