Activation of human platelets by 2-arachidonoylglycerol: Role of PKC in NO/cGMP pathway modulation

Maria Grazia Signorello, Enrica Giacobbe, Alessia Segantin, Luciana Avigliano, Fabiola Sinigaglia, Mauro Maccarrone, Giuliana Leoncini

Research output: Contribution to journalArticle

Abstract

We demonstrated that the endocannabinoid 2-arachidonoylglycerol (2-AG) activated dose-dependently washed human platelets and increased intracellular calcium levels. Moreover 2-AG activated protein kinase C measured as p47pleckstrin phosphorylation. These parameters were prevented by the tromboxane A 2 receptor antagonist SQ29548, by phospholipase C pathway (U73122) and protein kinase C (GF109203X) inhibitors. No effect on 2-AG-induced platelet activation and calcium elevation in the presence of inhibitors of fatty acid amide hydrolase or monoacylglycerol lipase was observed. In addition we have shown that 2-AG dose-dependently increased NO and cGMP levels. These effects were abolished by U73122, GF109203X, EGTA and the intracellular calcium chelator BAPTA/AM. Moreover, 2-AG enhanced eNOS activity through the phosphorylation of its positive regulatory residue ser1177 and by dephosphorylation of the negative one thr495. The eNOS ser1177 phosphorylation was inhibited by U73122 and GF109203X but it was unaffected by the PI3K/AKT pathway inhibitors LY294002 and MK2206. The dephosphorylation of thr495 was reversed by low concentrations of calyculin A. Taken together these data suggest that 2-AG behaves as a true platelet agonist stimulating PKC activation and calcium elevation. Likely 2-AG can modulate platelet activation by increasing NO levels through eNOS activation.

Original languageEnglish
Pages (from-to)200-209
Number of pages10
JournalCurrent Neurovascular Research
Volume8
Issue number3
DOIs
Publication statusPublished - Aug 2011

Keywords

  • 2-Arachidonoylglycerol
  • Enos phosphorylation/dephosphorylation
  • Human platelets
  • Nitric oxide
  • PKC
  • PP1
  • PP2A

ASJC Scopus subject areas

  • Neurology
  • Developmental Neuroscience
  • Cellular and Molecular Neuroscience

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