Glycosphingolipid inhibition of the adhesion of thrombin-activated platelets to surfaces is potentiated by albumin

Mark T. Cunningham, John D. Olson, Theodore A.W. Koerner

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Previous studies have shown that exogenous glycosphingolipids (GSLs) inhibit the adhesion of thrombin-activated platelets (TAP) to polystyrene plates coated with various RGD-ligands (where RGD is the peptide sequence Arg-Gly-Asp), suggesting that GSLs can modulate the platelet integrin receptor glycoprotein IIb-IIIa. However, albumin was always used as a plastic surface-blocking agent in these studies. In order to evaluate the role of albumin in these experiments, we studied the effect of various GSLs and albumin on the interaction between TAP and hydrophobic surfaces in a solid-phase assay using indium-111-labelled platelets and polystyrene plates. TAP (108 platelets/ml) adhered to polystyrene (half-saturation time 40 ± 3 min) with a maximal adhesion density of 56 ± 1×103 platelets/mm2. Platelet adhesion was only slightly affected (<11% inhibition) by immobilized bovine serum albumin, immobilized mixed bovine brain gangliosides (MBG) or fluid-phase MBG. In contrast, fluid-phase MBG was an effective inhibitor of platelet adhesion to polystyrene (>46% inhibition), but only after albumin was first immobilized to the plate. Covering albumin-coated polystyrene with MBG, followed by washing, was as effective as fluid-phase MBG at inhibiting platelet adhesion, thus indicating that a ganglioside-albumin interaction at the polystyrene surface was responsible for effective inhibition. When purified GSLs were substituted for MBG, it was found that all those tested (GT1b, GD1a, GM1, asialo GM1 and globoside) had similar inhibitory activity. Thus, GSLs non-specifically inhibit the platelet-polystyrene interaction after albumin potentiation, in which it appears there is formation of GSL-albumin complexes on plastic surfaces. These findings provide a better basis on which the results of any cellular adherence study involving GSLs, albumin and hydrophobic surfaces may be properly interpreted.

Original languageEnglish (US)
Pages (from-to)331-337
Number of pages7
JournalGlycobiology
Volume3
Issue number4
DOIs
StatePublished - Aug 1 1993

Keywords

  • Adhesion
  • Albumin
  • Glycosphingolipids
  • Platelets
  • Surface interaction

ASJC Scopus subject areas

  • Biochemistry

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