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Oxidized LDL activates blood platelets through CD36/NOX2–mediated inhibition of the cGMP/protein kinase G signaling cascade

Magwenzi, S.; Febbriao, M.; Kearney, M.; Naseem, K. M.; Woodward, C.; Wraith, K. S.; Aburima, A.; Raslan, Z.; Jones, H.; McNeil, C.; Wheatcroft, S.; Yuldasheva, N.

Authors

S. Magwenzi

C. Woodward

K. S. Wraith

A. Aburima

Z. Raslan

C. McNeil

S. Wheatcroft

N. Yuldasheva

M. Febbriao

M. Kearney

K. M. Naseem

Abstract

Oxidized low-density lipoprotein (oxLDL) promotes unregulated platelet activation in dyslipidemic disorders. Although oxLDL stimulates activatory signaling, it is unclear how these events drive accelerated thrombosis. Here, we describe a mechanism for oxLDL-mediated platelet hyperactivity that requires generation of reactive oxygen species (ROS). Under arterial flow, oxLDL triggered sustained generation of platelet intracellular ROS, which was blocked by CD36 inhibitors, mimicked by CD36-specific oxidized phospholipids, and ablated in CD36−/− murine platelets. oxLDL-induced ROS generation was blocked by the reduced NAD phosphate oxidase 2 (NOX2) inhibitor, gp91ds-tat, and absent in NOX2−/− mice. The synthesis of ROS by oxLDL/CD36 required Src-family kinases and protein kinase C (PKC)-dependent phosphorylation and activation of NOX2. In functional assays, oxLDL abolished guanosine 3′,5′-cyclic monophosphate (cGMP)-mediated signaling and inhibited platelet aggregation and arrest under flow. This was prevented by either pharmacologic inhibition of NOX2 in human platelets or genetic ablation of NOX2 in murine platelets. Platelets from hyperlipidemic mice were also found to have a diminished sensitivity to cGMP when tested ex vivo, a phenotype that was corrected by infusion of gp91ds-tat into the mice. This study demonstrates that oxLDL and hyperlipidemia stimulate the generation of NOX2-derived ROS through a CD36-PKC pathway and may promote platelet hyperactivity through modulation of cGMP signaling.

Journal Article Type Article
Publication Date Apr 23, 2015
Journal Blood
Print ISSN 0006-4971
Electronic ISSN 1528-0020
Publisher American Society of Hematology
Peer Reviewed Peer Reviewed
Volume 125
Issue 17
Pages 2693-2703
Institution Citation Magwenzi, S., Woodward, C., Wraith, K. S., Aburima, A., Raslan, Z., Jones, H., …Naseem, K. M. (2015). Oxidized LDL activates blood platelets through CD36/NOX2–mediated inhibition of the cGMP/protein kinase G signaling cascade. Blood, 125(17), 2693-2703. doi:10.1182/blood-2014-05-574491
DOI https://doi.org/10.1182/blood-2014-05-574491
Keywords Oxidized low-density lipoprotein; Blood platelets; Cardiovascular disease
Publisher URL http://www.bloodjournal.org/content/125/17/2693.article-info
Additional Information This is a description of an article which has been published in: Blood, 2015, v.125, issue 17