Journal of Lipid Research (Nov 2015)

Modification of platelet proteins by malondialdehyde: prevention by dicarbonyl scavengers[S]

  • Irene Zagol-Ikapite,
  • Iberia R. Sosa,
  • Denise Oram,
  • Audra Judd,
  • Kalyani Amarnath,
  • Venkataraman Amarnath,
  • Donald Stec,
  • John A. Oates,
  • Olivier Boutaud

Journal volume & issue
Vol. 56, no. 11
pp. 2196 – 2205

Abstract

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The thromboxane synthase converts prostaglandin H2 to thromboxane A2 and malondialdehyde (MDA) in approximately equimolar amounts. A reactive dicarbonyl, MDA forms covalent adducts of amino groups, including the ε-amine of lysine, but the importance of this reaction in platelets was unknown. Utilizing a novel LC/MS/MS method for analysis of one of the MDA adducts, the dilysyl-MDA cross-link, we demonstrated that dilysyl-MDA cross-links in human platelets are formed following platelet activation via the cyclooxygenase (COX)-1/thromboxane synthase pathway. Salicylamine and analogs of salicylamine were shown to react with MDA preferentially, thereby preventing formation of lysine adducts. Dilysyl-MDA cross-links were measured in two diseases known to be associated with increased platelet activation. Levels of platelet dilysyl-MDA cross-links were increased by 2-fold in metabolic syndrome relative to healthy subjects, and by 1.9-fold in sickle cell disease (SCD). In patients with SCD, the reduction of platelet dilysyl-MDA cross-links following administration of nonsteroidal anti-inflammatory drug provided evidence that MDA modifications of platelet proteins in this disease are derived from the COX pathway. In summary, MDA adducts of platelet proteins that cross-link lysines are formed on platelet activation and are increased in diseases associated with platelet activation. These protein modifications can be prevented by salicylamine-related scavengers.

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