Interleukin-8 binds to syndecan-2 on human endothelial cells

Biochem J. 2004 Jan 15;377(Pt 2):533-8. doi: 10.1042/BJ20030729.

Abstract

Application of reverse transcription-PCR to total RNA prepared from TNF-alpha (tumour necrosis factor-alpha)-stimulated HUVECs (human umbilical vein endothelial cells) revealed that the syndecan-2 mRNA was up-regulated by this inflammatory stimulus. By immunoprecipitation using an anti-syndecan-2 antibody on TNF-alpha-stimulated HUVEC lysates, inflammation-induced interleukin-8 was found to be an interaction partner of this HS (heparan sulphate) proteoglycan, but not of any other syndecan on these cells. The glycosylated [Syn2(ect)(+HS)] and non-glycosylated [Syn2(ect)(-HS)] forms of Syn2(ect) (the syndecan-2 ectodomain) were purified from a stably transfected human cell line and from a bacterial expression system respectively. By CD spectroscopy, Syn2(ect) was found to adopt an all-beta secondary structure. The dissociation constant of Syn2(ect)(+HS) with respect to interleukin-8 binding was determined by isothermal fluorescence titrations to be 23 nM. Despite its lack of HS chains, Syn2(ect)(-HS) exhibited significant binding to the chemokine, with a K (d) of >1 microM. Thus, in addition to glycosaminoglycan binding, protein-protein contacts might also contribute to the chemokine-proteoglycan interaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cells, Cultured
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism*
  • Glycosylation
  • Humans
  • Interleukin-8 / metabolism*
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / metabolism*
  • Protein Structure, Secondary
  • Proteoglycans / chemistry
  • Proteoglycans / metabolism*
  • Syndecan-2
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • Interleukin-8
  • Membrane Glycoproteins
  • Proteoglycans
  • SDC2 protein, human
  • Tumor Necrosis Factor-alpha
  • Syndecan-2