Sphingosine 1-Phosphate Produced by Sphingosine Kinase 2 Intrinsically Controls Platelet Aggregation In Vitro and In Vivo

• Published in: Circulation research Vol. 117; no. 4; pp. 376 - 387
• Main Authors: Urtz, Nicole, Gaertner, Florian, von Bruehl, Marie-Luise, Chandraratne, Sue, Rahimi, Faridun, Zhang, Lin, Orban, Mathias, Barocke, Verena, Beil, Johannes, Schubert, Irene, Lorenz, Michael, Legate, Kyle R, Huwiler, Andrea, Pfeilschifter, Josef M, Beerli, Christian, Ledieu, David, Persohn, Elke, Billich, Andreas, Baumruker, Thomas, Schnitzler, Michael Mederos y, Massberg, Steffen
• Format: Journal Article
• Language: English
• Published: United States American Heart Association, Inc 31.07.2015
• Subjects: Animals; Arachidonic Acid - blood; Blood Coagulation; Blood Coagulation Tests; Blood Platelets - enzymology; Carotid Artery Injuries - blood; Carotid Artery Injuries - enzymology; Disease Models, Animal; Erythrocytes - enzymology; Lysophospholipids - blood; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Phosphotransferases (Alcohol Group Acceptor) - blood; Phosphotransferases (Alcohol Group Acceptor) - deficiency; Phosphotransferases (Alcohol Group Acceptor) - genetics; Platelet Adhesiveness; Platelet Aggregation; Platelet Function Tests; Receptors, Lysosphingolipid - blood; Signal Transduction; Sphingosine - analogs & derivatives; Sphingosine - blood; Thrombosis - blood; Thrombosis - enzymology; Thrombosis - prevention & control; Thromboxane A2 - blood; Vascular System Injuries - blood; Vascular System Injuries - enzymology; blood platelets; thrombosis; sphingosine 1-phosphate; sphingosine kinase; platelet aggregation
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/CIRCRESAHA.115.306901

RATIONALE:Platelets are known to play a crucial role in hemostasis. Sphingosine kinases (Sphk) 1 and 2 catalyze the conversion of sphingosine to the bioactive metabolite sphingosine 1-phosphate (S1P). Although platelets are able to secrete S1P on activation, little is known about a potential intrinsic effect of S1P on platelet function. OBJECTIVE:To investigate the role of Sphk1- and Sphk2-derived S1P in the regulation of platelet function. METHODS AND RESULTS:We found a 100-fold reduction in intracellular S1P levels in platelets derived from Sphk2 mutants compared with Sphk1 or wild-type mice, as analyzed by mass spectrometry. Sphk2 platelets also failed to secrete S1P on stimulation. Blood from Sphk2-deficient mice showed decreased aggregation after protease-activated receptor 4-peptide and adenosine diphosphate stimulation in vitro, as assessed by whole blood impedance aggregometry. We revealed that S1P controls platelet aggregation via the sphingosine 1-phosphate receptor 1 through modulation of protease-activated receptor 4-peptide and adenosine diphosphate–induced platelet activation. Finally, we show by intravital microscopy that defective platelet aggregation in Sphk2-deficient mice translates into reduced arterial thrombus stability in vivo. CONCLUSIONS:We demonstrate that Sphk2 is the major Sphk isoform responsible for the generation of S1P in platelets and plays a pivotal intrinsic role in the control of platelet activation. Correspondingly, Sphk2-deficient mice are protected from arterial thrombosis after vascular injury, but have normal bleeding times. Targeting this pathway could therefore present a new therapeutic strategy to prevent thrombosis.