title: Nicotine upregulates the expression of P2Y12 on vascular cells and megakaryoblasts.
abstract: BACKGROUND
  P2Y12 is the major platelet receptor that mediates ADP-induced aggregation. P2Y12 is also expressed by vascular cells. The factors that regulate P2Y12 expression have not been determined. Since nicotine (NIC) has effects on platelet activation and vascular function, and because nicotinic and purinerigic receptors may interact, we determined whether nicotine altered P2Y12 expression.
  
  
  METHODS
  Four cell lines (human coronary artery endothelial cells, HCAEC; human umbilical vein endothelial cells, HUVEC; human aortic smooth muscle cells, HASMC; and human megakaryoblastic cells, MEG-01) were cultured in the absence or presence of nicotine. Immunoblotting for P2Y12, P2Y2, and actin was performed.
  
  
  RESULTS
  Nicotine, at concentrations of 0.1-1.0 microM, induced P2Y12 (but not P2Y2) expression in all the four cell lines. HASMC exhibited the greatest induction with a sixfold mean increase in P2Y12 expression in response to 0.25 microM nicotine. The induction was inhibited by nicotinic acetylcholine receptor antagonists. Healthy smokers were observed to have higher P2Y12 expression in platelet lysates compared to non-smokers.
  
  
  CONCLUSIONS
  Nicotine induces the expression of P2Y12 in vascular cells and megakaryoblasts, and is mediated by nicotinic acetylcholine receptors. Smokers exhibit higher platelet P2Y12, possibly mediated via nicotine. These results may contribute to a better understanding of the effects of cigarette smoking on platelet activation and the vessel wall.
  
  
  CONCLUSIONS
  The factors that regulate the expression of P2Y12, the platelet ADP receptor, have not been determined. Four cell lines (human coronary artery endothelial cells, HCAEC; human umbilical vein endothelial cells, HUVEC; human aortic smooth muscle cells, HASMC; and human megakaryoblastic cells, MEG-01) were cultured in the absence or presence of nicotine. Nicotine, at concentrations of 0.1-1.0 microM, induced P2Y12 expression in all the four cell lines. HASMC exhibited the greatest induction with a sixfold mean increase in P2Y12 expression in response to 0.25 microM nicotine. The induction was inhibited by nicotinic acetylcholine receptor antagonists. Healthy smokers were observed to have higher P2Y12 expression in platelet lysates compared to non-smokers. These results may contribute to a better understanding of the effects of cigarette smoking on platelet activation and the vessel wall.
authors.affiliation: Section of Cardiology, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1045, USA.
authors.forename: Gouri
authors.initials: G
authors.lastname: Shanker
authors.forename: Jimmy L
authors.initials: JL
authors.lastname: Kontos
authors.forename: Delrae M
authors.initials: DM
authors.lastname: Eckman
authors.forename: Deborah
authors.initials: D
authors.lastname: Wesley-Farrington
authors.forename: David C
authors.initials: DC
authors.lastname: Sane
mesh_terms: D000328:Adult; D042783:Endothelial Cells / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008533:Megakaryocytes / Q000378:metabolism*; D008875:Middle Aged; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D015539:Platelet Activation / Q000187:drug effects; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058925:Receptors, Purinergic P2Y12; D012907:Smoking / Q000009:adverse effects; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D018722:Nicotinic Agonists; C548576:P2RY12 protein, human; D018048:Receptors, Purinergic P2; D058925:Receptors, Purinergic P2Y12; D009538:Nicotine