Regulation of functionally active P2Y12 ADP receptors by thrombin in human smooth muscle cells and the presence of P2Y12 in carotid artery lesions.
OBJECTIVE
The platelet P2Y12 ADP receptor is a well-known target of thienopyridine-type antiplatelet drugs. This study is the first to describe increased transcriptional expression of a functionally active P2Y12 in response to thrombin in human vascular smooth muscle cells (SMC).


RESULTS
On exposure to thrombin, P2Y12 mRNA was transiently increased, whereas total protein and cell surface expression of P2Y12 were markedly increased within 6 hours and remained elevated over 24 hours. This effect was mediated by activation of nuclear factor κB. Preincubation with thrombin significantly enhanced the efficacy of the P2Y receptor agonist 2-methylthio-ADP to induce interleukin 6 expression and SMC mitogenesis. Effects induced by 2-methylthio-ADP were prevented by RNA interference-mediated knockdown of P2Y12 and a selective P2Y12-antagonist R-138727, the active metabolite of prasugrel. In addition, positive P2Y12 immunostaining was shown in SMC of human carotid artery plaques and was found to colocalize with tissue factor, the rate-limiting factor of thrombin formation in vivo.


CONCLUSIONS
These data suggest that the P2Y12 receptor not only is central to ADP-induced platelet activation but also may mediate platelet-independent responses, specifically under conditions of enhanced thrombin formation, such as local vessel injury and atherosclerotic plaque rupture.
Institut für Pharmakologie und Klinische Pharmakologie, Universitätsklinikum Düsseldorf, Germany.
Bernhard H
BH
Rauch
Anke C
AC
Rosenkranz
Swen
S
Ermler
Andreas
A
Böhm
Julia
J
Driessen
Jens W
JW
Fischer
Atsuhiro
A
Sugidachi
Joseph A
JA
Jakubowski
Karsten
K
Schrör
D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D002340:Carotid Artery Diseases / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology; D058912:Purinergic P2Y Receptor Agonists / Q000494:pharmacology; D058921:Purinergic P2Y Receptor Antagonists / Q000494:pharmacology; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D058925:Receptors, Purinergic P2Y12 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013873:Thionucleotides / Q000494:pharmacology; D013917:Thrombin / Q000378:metabolism*; D013997:Time Factors; D015533:Transcriptional Activation / Q000187:drug effects; D015854:Up-Regulation
C508600:IL6 protein, human; D015850:Interleukin-6; D016328:NF-kappa B; C548576:P2RY12 protein, human; D010879:Piperazines; D058912:Purinergic P2Y Receptor Agonists; D058921:Purinergic P2Y Receptor Antagonists; C510685:R-138727; D012333:RNA, Messenger; D058925:Receptors, Purinergic P2Y12; D013873:Thionucleotides; C002480:methylthio-ADP; D000244:Adenosine Diphosphate; D000242:Cyclic AMP; D013917:Thrombin