Disease relevance of P2RY12

• Here we show that at the relatively high concentration of agonist most likely found at the site of a local thrombus, dual inhibition of the P2Y12 receptor and calcium mobilization result in a complete inhibition of PAR4-induced aggregation, while having no effect on either thrombin or PAR1-mediated platelet aggregation [1].
• HORK3, when transfected in the rat glioma cell subline (C6-15), responded to 2-methylthio-ADP (2MeSADP) (EC(50) = 0.08 nM) and ADP (EC(50) = 42 nM) with inhibition of forskolin-stimulated cAMP accumulation [2].
• In conclusion, microaggregates of platelets via P2Y12 receptors could play a key role in the hypersensitivity of platelets in diabetic patients, and the measurement of microaggregation could be a useful marker to estimate of thrombogenesis [3].
• The P2Y12-mediated stimulation of proliferation required the pertussis toxin-sensitive activation of PI3-kinase/Akt upstream of MAP-kinases [4].
• Both analogues were inactive (IC50>10 microM) as antagonists of human P2Y12 receptor-mediated PLC responses in 1321N1 astrocytoma cells [5].

High impact information on P2RY12

• The molecular identity of the Gi-linked receptor is still elusive, even though it is the target of efficacious antithrombotic agents, such as ticlopidine and clopidogrel and AR-C66096 (ref. 9). Here we describe the cloning of this receptor, designated P2Y12, and provide evidence that a patient with a bleeding disorder has a defect in this gene [6].
• Central role of the P2Y12 receptor in platelet activation [7].
• This study was designed to determine the role of P2Y12 in platelet thrombosis and how its complete absence affects the thrombotic process [8].
• Using an in vivo mesenteric artery injury model and real-time continuous analysis of the thrombotic process, we observed that the time for appearance of first thrombus was delayed and that only small, unstable thrombi formed in P2Y12-/- mice without reaching occlusive size, in the absence of aspirin [8].
• The raft-associated P2Y12 oligomers represented the functional form of the receptor, as demonstrated by binding and signal transduction studies [9].

Chemical compound and disease context of P2RY12

• Due to its central role in the formation and stabilization of a thrombus, the P2Y12 receptor is a well-established target of antithrombotic drugs like ticlopidine or clopidogrel, which have proved efficacy in many clinical trials and experimental models of thrombosis [10].
• Further analysis of the rat brain pIC50 data against those available for three of the AR-C compounds in reversing P2Y12-mediated adenylyl cyclase inhibition in rat platelets (r2=0.96) and rat C6 glioma cells (r2=1.00) demonstrated that the three P2Y receptors are pharmacologically indistinguishable [11].

Biological context of P2RY12

• Reciprocal cross-talk between P2Y1 and P2Y12 receptors at the level of calcium signaling in human platelets [12].
• P2Y12 receptor inhibitors clinically in use such as clopidogrel are postulated to decrease platelet aggregation through partial inhibition of PAR1 signaling [1].
• We demonstrate that a set of proteins of 27, 29, 31, 34, and 39 kDa is affected by released ADP and P2Y12 receptor signaling during platelet activation [13].
• P2Y12 ADP receptor-dependent tyrosine phosphorylation of proteins of 27 and 31 kDa in thrombin-stimulated human platelets [13].
• Molecular bases of defective signal transduction in the platelet P2Y12 receptor of a patient with congenital bleeding [14].

Anatomical context of P2RY12

• In an effort to identify ligands for SP1999, fractionated rat spinal cord extracts were assayed for Ca(2+) mobilization activity against Chinese hamster ovary cells transiently transfected with SP1999 and chimeric Galpha subunits (Galpha(q/i)) [15].
• We conclude that ADP released from red blood cells enhances PMP formation induced by collagen, and that both P2Y12 and P2Y1 contribute to ADP-potentiation of PMP generation induced by collagen [16].
• Plasma membranes from ADP-stimulated platelets also retained P2Y12 activity [17].
• Lack of association between the P2Y12 receptor gene polymorphism and platelet response to clopidogrel in patients with coronary artery disease [18].
• Here, we show that stimulation of the human P2Y12 receptor stably expressed in Chinese hamster ovary cells activates two major intracellular signaling mechanisms leading either to cell proliferation or to actin cytoskeleton reorganization [4].

Associations of P2RY12 with chemical compounds

• Other nucleotides were able to activate SP1999 with a rank order of potency 2-MeS-ATP = 2-MeS-ADP > ADP = adenosine 5'-O-2-(thio)diphosphate > 2-Cl-ATP > adenosine 5'-O-(thiotriphosphate) [15].
• Besides the ADP analogue 2-MeS-ADP, other platelet agonists such as collagen and the TXA(2)-mimetic U46619 also induce p27 and p31 tyrosine phosphorylation in a P2Y12 receptor-dependent manner [13].
• Blockade of ADP receptors, P2Y12 with AR-C69931MX and P2Y1 with A3P5P, respectively, further suppressed collagen-induced PMP formation [16].
• P2Y12 is known to couple to activation of PI3 kinase and inhibition of adenylate cyclase, but we showed that neither of these signalling events couples to regulation of shape change by this receptor [19].
• Inactivation of the human P2Y12 receptor by thiol reagents requires interaction with both extracellular cysteine residues, Cys17 and Cys270 [20].
• Stimulation of P2Y12 receptor or direct inhibition of diacylglycerol kinase potentiated the effect of membrane-permeable sn-1,2-dioctanoylglycerol on platelet aggregation and pleckstrin phosphorylation, in association with inhibition of its phosphorylation to phosphatidic acid [21].

Physical interactions of P2RY12

• Adenosine diphosphate (ADP) initiates and maintains sustained aggregation of platelets through simultaneous activation of both the Gq-coupled P2Y1 receptor and the Gi-coupled P2Y12 receptor [22].

Regulatory relationships of P2RY12

• These results further demonstrate the P2Y1 receptor selectivity of MRS2365 and illustrate the occurrence of agonist-induced desensitization of the P2Y1 receptor of human platelets studied in the absence of P2Y12 receptor activation [22].
• We conclude that P2Y12 plays a potentiatory role in ADP-induced shape change through regulation of the Rho kinase pathway, potentiating both myosin phosphorylation and actin polymerisation, and this forms part of an important signalling pathway additional to its well-established Gi-coupled pathways [19].
• To address the mechanism that regulates alphavbeta3 activity in platelets, we measured the effect of the P2Y1 antagonist adenosine 3'-phosphate-5'-phosphate (A3P5P) and the P2Y12 antagonist AR-C66096 on ADP-stimulated platelet adhesion to osteopontin and vitronectin [23].
• BACKGROUND: Insulin inhibits platelet aggregation by suppressing the P2Y12 pathway [24].

Other interactions of P2RY12

• The relative importance of the ADP receptors, P2Y12 and P2Y1, in thrombin-induced platelet activation [25].
• ADP activates human platelets through two G-protein coupled receptors, P2Y1 and P2Y12, to induce a range of functional responses [19].
• Activation of Rap1B induced by thrombin was not affected by preincubation of platelets with the anti-GPIbalpha monoclonal antibody AK2 in the absence of ADP scavengers or a P2Y12 antagonist but was totally abolished when secreted ADP was neutralized or after blockade of the P2Y12 receptor [26].
• MRS2365, an (N)-methanocarba analogue of 2-MeSADP, displayed potency (EC50) of 0.4nM at the P2Y1 receptor, with >10000-fold selectivity in comparison to P2Y12 and P2Y13 receptors [27].
• Conversely, the P2Y12-mediated reorganization of the actin cytoskeleton was Gi-independent, requiring activation of RhoA and Rho-kinase [4].

Analytical, diagnostic and therapeutic context of P2RY12

• P2Y12 H2 haplotype is associated with peripheral arterial disease: a case-control study [28].
• However, accumulation of GTP-bound Rap1B in platelets activated by co-stimulation of cMpl and P2Y12 receptor was identical to that induced by the simultaneous ligation of P2Y1 and P2Y12 receptor by ADP [29].
• Competitive P2Y12 antagonists have also been shown to be effective in experimental thrombosis as well as in several clinical trials [10].
• These P2Y12-antagonists are used in pharmacotherapy to inhibit platelet aggregation [30].
• Reverse transcription polymerase chain reaction (RT-PCR) showed the expression of P2Y1, P2Y2 and P2Y12 [31].

References