title: Inhibition of thrombin-induced signaling by resveratrol and quercetin: effects on adenosine nucleotide metabolism in endothelial cells and platelet-neutrophil interactions.
abstract: BACKGROUND
  Thrombin downregulates endothelial ectonucleotidase activity resulting in high levels of adenosine diphosphate (ADP) and adenosine triphosphate (ATP) which lead to platelet, leukocyte and endothelial activation. Depending on adenosine nucleotide levels, resting platelets inhibit and thrombin-activated platelets increase respiratory burst of neutrophils. Whether the red wine polyphenols quercetin and resveratrol affect thrombin-dependent adenosine nucleotide, metabolism and thrombin-induced signaling is unknown.
  
  
  METHODS
  ATP and ADP secretion by platelets, the impact on subsequent oxidative burst activity in neutrophils and CD39/ATPdase function in endothelial cells (ECs)was studied. Cell migration was measured in modified Boyden chambers; adenosine metabolites were quantified by high-performance liquid chromatography (HPLC). Signal transduction was studied by Western blotting.
  
  
  RESULTS
  Quercetin and resveratrol inhibited thrombin-induced ADP and ATP secretion from platelets in a concentration-dependent manner. Augmented respiratory burst of neutrophils in response to thrombin-activated platelets was also inhibited by the two polyphenols as was neutrophil migration toward thrombin-induced supernatants of platelets. Quercetin and resveratrol restored the decreased CD39/ATPdase activity in human umbilical vein endothelial cells, in response to thrombin as demonstrated by adenosine monophosphate (AMP) and adenosine increases in endothelial culture supernatants. Both polyphenols inhibited thrombin-induced MAPK, JNK and focal adhesion kinase activities in endothelial cells.
  
  
  CONCLUSIONS
  Quercetin and resveratrol interfere with the proinflammatory signaling of thrombin resulting in the inhibition of adenosine nucleotide secretion from activated platelets and decreased neutrophil function. Moreover, the polyphenols protect endothelial adenosine nucleotide metabolism when downregulated by thrombin. These observations may explain cardioprotective effects of grape products.
authors.affiliation: Department of General Internal Medicine, University of Innsbruck, Anichstrasse 35, A-6020, Austria.
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Kaneider
authors.forename: Birgit
authors.initials: B
authors.lastname: Mosheimer
authors.forename: Norbert
authors.initials: N
authors.lastname: Reinisch
authors.forename: Josef R
authors.initials: JR
authors.lastname: Patsch
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Wiedermann
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D011794:Quercetin / Q000494:pharmacology*; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013267:Stilbenes / Q000494:pharmacology*; D013917:Thrombin / Q000378:metabolism*
chemical_list: D000227:Adenine Nucleotides; D000975:Antioxidants; D010975:Platelet Aggregation Inhibitors; D013267:Stilbenes; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D011794:Quercetin; D013917:Thrombin; D000077185:Resveratrol