Increased platelet activation and thrombosis in transgenic mice expressing constitutively active P2Y12.
BACKGROUND
In our previous in vitro study, we reported a constitutively active chimeric P2Y(12) (cP2Y(12)) and found that AR-C78511 is a potent inverse agonist at this receptor. The role of cP2Y(12) in platelet activation and thrombosis is not clear.


OBJECTIVE
To investigate the physiologic implications of cP2Y(12) for platelet activation and thrombus formation, and to evaluate the antiplatelet activity of AR-C78511 as an inverse agonist.


RESULTS
We generated transgenic mice conditionally and platelet-specifically expressing cP2Y(12). High-level expression of cP2Y(12) in platelets increased platelet reactivity, as shown by increased platelet aggregation in response to multiple platelet agonists. Moreover, transgenic mice showed a shortened bleeding time, and more rapid and stable thrombus formation in mesenteric artery injured with FeCl(3). The constitutive activity of cP2Y(12) in platelets was confirmed by decreased platelet cAMP levels and constitutive Akt phosphorylation in the absence of agonists. AR-C78511 reversed the cAMP decrease in transgenic mouse platelets, and exhibited a superior antiplatelet effect to that of AR-C69931MX in transgenic mice.


CONCLUSIONS
These findings further emphasize the importance of P2Y(12) in platelet activation, hemostasis, and thrombosis, as well as the prothrombotic role of the constitutive activity of P2Y(12). Our data also validate the in vivo inverse agonist activity of AR-C78511, and confirm its superior antiplatelet activity over neutral antagonists.
Key Laboratory of Molecular Medicine, Ministry of Education and Department of Biochemistry and Molecular Biology, Fudan University Shanghai, China.
Y
Y
Zhang
J
J
Ye
L
L
Hu
S
S
Zhang
S H
SH
Zhang
Y
Y
Li
S P
SP
Kunapuli
Z
Z
Ding
D000249:Adenosine Monophosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001760:Bleeding Time; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002712:Chlorides; D000242:Cyclic AMP / Q000097:blood; D004195:Disease Models, Animal; D054314:Drug Inverse Agonism; D005290:Ferric Compounds; D005343:Fibrinolytic Agents / Q000494:pharmacology; D005838:Genotype; D051379:Mice; D008822:Mice, Transgenic; D010641:Phenotype; D010766:Phosphorylation; D015539:Platelet Activation / Q000187:drug effects / Q000235:genetics; D010974:Platelet Aggregation; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000097:blood; D058921:Purinergic P2Y Receptor Antagonists / Q000494:pharmacology; D058925:Receptors, Purinergic P2Y12 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013927:Thrombosis / Q000097:blood* / Q000139:chemically induced / Q000235:genetics / Q000517:prevention & control
D002712:Chlorides; D005290:Ferric Compounds; D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D058921:Purinergic P2Y Receptor Antagonists; D058925:Receptors, Purinergic P2Y12; D000249:Adenosine Monophosphate; C117446:cangrelor; D000242:Cyclic AMP; D051057:Proto-Oncogene Proteins c-akt; C024555:ferric chloride