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Nitric oxide inhibits von Willebrand factor-mediated platelet adhesion and spreading through regulation of integrin α IIbβ 3 and myosin light chain

Roberts, W.; Michno, A.; Aburima, A.; Naseem, K. M.


W. Roberts

A. Michno

A. Aburima

K. M. Naseem


Background: von Willebrand factor (VWF)-mediated platelet adhesion and spreading at sites of vascular injury is a critical step in hemostasis. This process requires two individual receptors: glycoprotein Ib (GPIb)-V-IX and integrin αIIbβ3. However, little is known about the negative regulation of these events. Objectives: To examine if the endogenous platelet inhibitor nitric oxide (NO) has differential effects on adhesion, spreading and aggregation induced by immobilized VWF. Results: S-nitrosoglutathione (GSNO) inhibited platelet aggregation on immobilized VWF under static and flow conditions, but had no effect on platelet adhesion. Primary signaling events underpinning the actions of NO required cyclic GMP but not protein kinase A. Dissecting the roles of GPIb and integrin αIIbβ3 demonstrated that NO targeted αIIbβ3-mediated aggregation and spreading, but did not significantly influence GPIb-mediated adhesion. To understand the relationship between the effects of NO on adhesion and subsequent aggregation, we evaluated the activation of αIIbβ3 on adherent platelets. NO reduced the phosphorylation of extracellular stimuli-responsive kinase (ERK) and p38, required for integrin activation resulting in reduced binding of the activated αIIbβ3-specific antibody PAC-1 on adherent platelets. Detailed analysis of platelet spreading initiated by VWF demonstrated key roles for integrin αIIbβ3 and myosin light chain (MLC) phosphorylation. NO targeted both of these pathways by directly modulating integrin affinity and activating MLC phosphatase. Conclusion: These data demonstrate that initial activation-independent platelet adhesion to VWF via GPIb is resistant to NO, however, NO inhibits GPIb-mediated activation of αIIbβ3 and MLC leading to reduced platelet spreading and aggregation.


Roberts, W., Michno, A., Aburima, A., & Naseem, K. M. (2009). Nitric oxide inhibits von Willebrand factor-mediated platelet adhesion and spreading through regulation of integrin α IIbβ 3 and myosin light chain. Journal of thrombosis and haemostasis : JTH, 7(12), 2106-2115. doi:10.1111/j.1538-7836.2009.03619.x

Journal Article Type Article
Acceptance Date Sep 10, 2009
Online Publication Date Nov 23, 2009
Publication Date Dec 1, 2009
Deposit Date Nov 13, 2014
Journal Journal Of Thrombosis And Haemostasis
Print ISSN 1538-7933
Electronic ISSN 1538-7836
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 7
Issue 12
Pages 2106-2115
Keywords Adhesion; Nitric oxide; Platelet; Spreading; von Willebrand factor,
Public URL
Publisher URL
Additional Information Poor quality photocopy