P2Y12 protects platelets from apoptosis via PI3k-dependent Bak/Bax inactivation.

Abstract

BACKGROUND:

Platelet ADP receptor P2Y(12) is well studied and recognized as a key player in platelet activation, hemostasis and thrombosis. However, the role of P2Y(12) in platelet apoptosis remains unknown.

OBJECTIVES:

To evaluate the role of the P2Y(12) receptor in platelet apoptosis.

METHODS:

We used flow cytometry and Western blotting to assess apoptotic events in platelets treated with ABT-737 or ABT-263, and stored at 37°C, combined with P2Y(12) receptor antagonists or P2Y(12) -deficient mice.

RESULTS:

 P2Y(12) activation attenuated apoptosis induced by ABT-737 in human and mouse platelets in vitro, evidenced by reduced phosphatidylserine (PS) exposure, diminished depolarization of mitochondrial inner transmembrane potential (ΔΨm) and decreased caspase-3 activation. Through increasing the phosphorylation level of Akt and Bad, and changing the interaction between different Bcl-2 family proteins, P2Y(12) activation inactivated Bak/Bax. This antiapoptotic effect could be abolished by P2Y(12) antagonism or PI3K inhibition. We also observed the antiapoptotic effect of P2Y(12) activation in platelets stored at 37°C. P2Y(12) activation improved the impaired activation responses of apoptotic platelets stressed by ABT-737. In platelets from mice dosed with ABT-263 in vivo, clopidogrel or deficiency of P2Y(12) receptor enhanced apoptosis along with increased Bak/Bax activation.

CONCLUSIONS:

This study demonstrates that P2Y(12) activation protects platelets from apoptosis via PI3k-dependent Bak/Bax inactivation, which may be physiologically important to counter the proapoptotic challenge. Our findings that P2Y(12) blockade exaggerates platelet apoptosis induced by ABT-263 (Navitoclax) also imply a novel drug interaction of ABT-263 and P2Y(12) antagonists.

• Authors: S Zhang, J Ye, Y Zhang, X Xu, J Liu, S H Zhang, S P Kunapuli, Z Ding
• Journal: Journal of thrombosis and haemostasis : JTH (J Thromb Haemost) Vol. 11 Issue 1 Pg. 149-60 (Jan 2013) ISSN: 1538-7836 [Electronic] England
• PMID: 23140172 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2012 International Society on Thrombosis and Haemostasis.

Chemical References

• ABT-737
• Aniline Compounds
• BAD protein, human
• BAK1 protein, human
• BAX protein, human
• Bad protein, mouse
• Bak1 protein, mouse
• Bax protein, mouse
• Biphenyl Compounds
• Nitrophenols
• P2RY12 protein, human
• P2ry12 protein, mouse
• Phosphatidylserines
• Piperazines
• Protein Kinase Inhibitors
• Purinergic P2Y Receptor Antagonists
• Receptors, Purinergic P2Y12
• Sulfonamides
• bcl-2 Homologous Antagonist-Killer Protein
• bcl-2-Associated X Protein
• bcl-Associated Death Protein
• Phosphatidylinositol 3-Kinase
• Proto-Oncogene Proteins c-akt
• CASP3 protein, human
• Casp3 protein, mouse
• Caspase 3
• navitoclax

Topics

• Aniline Compounds (pharmacology)
• Animals
• Apoptosis (drug effects)
• Biphenyl Compounds (pharmacology)
• Blood Platelets (drug effects, enzymology, pathology)
• Blotting, Western
• Caspase 3 (blood)
• Dose-Response Relationship, Drug
• Flow Cytometry
• Humans
• Membrane Potential, Mitochondrial
• Mice
• Mice, Inbred C57BL
• Mice, Knockout
• Nitrophenols (pharmacology)
• Phosphatidylinositol 3-Kinase (blood)
• Phosphatidylserines (blood)
• Phosphorylation
• Piperazines (pharmacology)
• Protein Kinase Inhibitors (pharmacology)
• Proto-Oncogene Proteins c-akt (blood)
• Purinergic P2Y Receptor Antagonists (pharmacology)
• Receptors, Purinergic P2Y12 (blood, deficiency, drug effects, genetics)
• Signal Transduction
• Sulfonamides (pharmacology)
• Time Factors
• bcl-2 Homologous Antagonist-Killer Protein (blood)
• bcl-2-Associated X Protein (blood)
• bcl-Associated Death Protein (blood)