title: Efficiency of von Willebrand factor-mediated targeting of interleukin-8 into Weibel-Palade bodies.
abstract: BACKGROUND
  After de novo synthesis in endothelial cells, the chemokine interleukin-8 (IL-8) is targeted to endothelial cell-specific storage vesicles, the Weibel-Palade bodies (WPBs), where it colocalizes with von Willebrand factor (VWF).
  
  
  OBJECTIVE
  In this study we investigated a putative regulator function for VWF in the recruitment of IL-8 to WPBs.
  
  
  METHODS
  We performed a quantitative analysis of the entry of IL-8 into the storage system of the endothelium using pulse-chase analysis and subcellular fractionation studies.
  
  
  RESULTS
  Using pulse-chase analysis of IL-1beta-stimulated human umbilical vein endothelial cells, we found that a small part of de novo synthesized IL-8 was retained in endothelial cells after 4 h. In density gradients of endothelial cell homogenates nearly equimolar amounts of VWF and IL-8 were present in subcellular fractions that contained WPBs. Furthermore, we found that IL-8 binds to immobilized VWF under the slightly acidic conditions thought to prevail in the lumen of the late secretory pathway.
  
  
  CONCLUSIONS
  These observations indicate that the sorting efficiency of IL-8 into the regulated secretory pathway of the endothelium is tightly controlled by the entry of VWF into WPBs.
authors: Department of Plasma Proteins, Sanquin Research and Landsteiner Laboratory AMC, University of Amsterdam, Plesmanlaan 125, Amsterdam, The Netherlands.
authors: R
authors: R
authors: Bierings
authors: M
authors: M
authors: van den Biggelaar
authors: A
authors: A
authors: Kragt
authors: K
authors: K
authors: Mertens
authors: J
authors: J
authors: Voorberg
authors: J A
authors: JA
authors: van Mourik
mesh_terms: D001665:Binding Sites; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism*; D007700:Kinetics; D011485:Protein Binding; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism; D020302:Weibel-Palade Bodies / Q000378:metabolism*; D021601:trans-Golgi Network / Q000378:metabolism; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D053583:Interleukin-1beta; D016209:Interleukin-8; D014841:von Willebrand Factor; D013917:Thrombin