Activated α<sub>IIb</sub>β<sub>3</sub> on platelets mediates flow-dependent NETosis via SLC44A2.

Constantinescu-Bercu, Adela; Grassi, Luigi; Frontini, Mattia; Salles-Crawley, Isabelle I; Woollard, Kevin; Crawley, James Tb · Elife · 2020

basic_science · Level V

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Abstract

Platelet-neutrophil interactions are important for innate immunity, but also contribute to the pathogenesis of deep vein thrombosis, myocardial infarction and stroke. Here we report that, under flow, von Willebrand factor/glycoprotein Ibα-dependent platelet 'priming' induces integrin α<sub>IIb</sub>β<sub>3</sub> activation that, in turn, mediates neutrophil and T-cell binding. Binding of platelet α<sub>IIb</sub>β<sub>3</sub> to SLC44A2 on neutrophils leads to mechanosensitive-dependent production of highly prothrombotic neutrophil extracellular traps. A polymorphism in <i>SLC44A2</i> (rs2288904-A) present in 22% of the population causes an R154Q substitution in an extracellular loop of SLC44A2 that is protective against venous thrombosis results in severely impaired binding to both activated α<sub>IIb</sub>β<sub>3</sub> and VWF-primed platelets. This was confirmed using neutrophils homozygous for the <i>SLC44A2</i> R154Q polymorphism. Taken together, these data reveal a previously unreported mode of platelet-neutrophil crosstalk, mechanosensitive NET production, and provide mechanistic insight into the protective effect of the <i>SLC44A2</i> rs2288904-A polymorphism in venous thrombosis.

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