Efficiency of von Willebrand factor-mediated targeting of interleukin-8 into Weibel-Palade bodies

J Thromb Haemost. 2007 Dec;5(12):2512-9. doi: 10.1111/j.1538-7836.2007.02768.x. Epub 2007 Sep 19.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cells, Cultured
  • Endothelial Cells / metabolism*
  • Humans
  • Interleukin-1beta / metabolism
  • Interleukin-8 / metabolism*
  • Kinetics
  • Protein Binding
  • Protein Transport
  • Subcellular Fractions / metabolism
  • Thrombin / metabolism
  • Weibel-Palade Bodies / metabolism*
  • trans-Golgi Network / metabolism
  • von Willebrand Factor / metabolism*

Substances

  • Interleukin-1beta
  • Interleukin-8
  • von Willebrand Factor
  • Thrombin