TY - JOUR

T1 - The Ca2+/calmodulin-dependent kinase kinase β-AMP-activated protein kinase-α1 pathway regulates phosphorylation of cytoskeletal targets in thrombin-stimulated human platelets

AU - Onselaer, M. B.

AU - Oury, C.

AU - Hunter, R. W.

AU - Eeckhoudt, S.

AU - Barile, N.

AU - Lecut, C.

AU - Morel, N.

AU - Viollet, B.

AU - Jacquet, L. M.

AU - Bertrand, L.

AU - Sakamoto, K.

AU - Vanoverschelde, J. L.

AU - Beauloye, C.

AU - Horman, S.

PY - 2014/6

Y1 - 2014/6

N2 - Summary: Background: Platelet activation requires sweeping morphologic changes, supported by contraction and remodeling of the platelet actin cytoskeleton. In various other cell types, AMP-activated protein kinase (AMPK) controls the phosphorylation state of cytoskeletal targets. Objective: To determine whether AMPK is activated during platelet aggregation and contributes to the control of cytoskeletal targets. Results: We found that AMPK-α1 was mainly activated by thrombin, and not by other platelet agonists, in purified human platelets. Thrombin activated AMPK-α1 ex vivo via a Ca2+/calmodulin-dependent kinase kinase β (CaMKKβ)-dependent pathway. Pharmacologic inhibition of CaMKKβ blocked thrombin-induced platelet aggregation and counteracted thrombin-induced phosphorylation of several cytoskeletal proteins, namely, regulatory myosin light chains (MLCs), cofilin, and vasodilator-stimulated phosphoprotein (VASP), three key elements involved in actin cytoskeletal contraction and polymerization. Platelets isolated from mice lacking AMPK-α1 showed reduced aggregation in response to thrombin, and this was associated with defects in MLC, cofilin and VASP phosphorylation and actin polymerization. More importantly, we show, for the first time, that the AMPK pathway is activated in platelets of patients undergoing major cardiac surgery, in a heparin-sensitive manner. Conclusion: AMPK-α1 is activated by thrombin in human platelets. It controls the phosphorylation of key cytoskeletal targets and actin cytoskeletal remodeling during platelet aggregation.

AB - Summary: Background: Platelet activation requires sweeping morphologic changes, supported by contraction and remodeling of the platelet actin cytoskeleton. In various other cell types, AMP-activated protein kinase (AMPK) controls the phosphorylation state of cytoskeletal targets. Objective: To determine whether AMPK is activated during platelet aggregation and contributes to the control of cytoskeletal targets. Results: We found that AMPK-α1 was mainly activated by thrombin, and not by other platelet agonists, in purified human platelets. Thrombin activated AMPK-α1 ex vivo via a Ca2+/calmodulin-dependent kinase kinase β (CaMKKβ)-dependent pathway. Pharmacologic inhibition of CaMKKβ blocked thrombin-induced platelet aggregation and counteracted thrombin-induced phosphorylation of several cytoskeletal proteins, namely, regulatory myosin light chains (MLCs), cofilin, and vasodilator-stimulated phosphoprotein (VASP), three key elements involved in actin cytoskeletal contraction and polymerization. Platelets isolated from mice lacking AMPK-α1 showed reduced aggregation in response to thrombin, and this was associated with defects in MLC, cofilin and VASP phosphorylation and actin polymerization. More importantly, we show, for the first time, that the AMPK pathway is activated in platelets of patients undergoing major cardiac surgery, in a heparin-sensitive manner. Conclusion: AMPK-α1 is activated by thrombin in human platelets. It controls the phosphorylation of key cytoskeletal targets and actin cytoskeletal remodeling during platelet aggregation.

KW - AMP-activated protein kinase

KW - Cytoskeleton

KW - Platelet aggregation

KW - Signal transduction

KW - Thrombin

UR - http://www.scopus.com/inward/record.url?scp=84902076187&partnerID=8YFLogxK

U2 - 10.1111/jth.12568

DO - 10.1111/jth.12568

M3 - Journal article

C2 - 24655923

AN - SCOPUS:84902076187

VL - 12

SP - 973

EP - 986

JO - Journal of Thrombosis and Haemostasis

JF - Journal of Thrombosis and Haemostasis

SN - 1538-7933

IS - 6

ER -