Platelets induce neutrophil extracellular traps in transfusion-related acute lung injury
Axelle Caudrillier, … , Zena Werb, Mark R. Looney
Axelle Caudrillier, … , Zena Werb, Mark R. Looney
Published June 11, 2012
Citation Information: J Clin Invest. 2012;122(7):2661-2671. https://doi.org/10.1172/JCI61303.
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Research Article Pulmonology

Platelets induce neutrophil extracellular traps in transfusion-related acute lung injury

Abstract

There is emerging evidence that platelets are major contributors to inflammatory processes through intimate associations with innate immune cells. Here, we report that activated platelets induce the formation of neutrophil extracellular traps (NETs) in transfusion-related acute lung injury (TRALI), which is the leading cause of death after transfusion therapy. NETs are composed of decondensed chromatin decorated with granular proteins that function to trap extracellular pathogens; their formation requires the activation of neutrophils and release of their DNA in a process that may or may not result in neutrophil death. In a mouse model of TRALI that is neutrophil and platelet dependent, NETs appeared in the lung microvasculature and NET components increased in the plasma. We detected NETs in the lungs and plasma of human TRALI and in the plasma of patients with acute lung injury. In the experimental TRALI model, targeting platelet activation with either aspirin or a glycoprotein IIb/IIIa inhibitor decreased NET formation and lung injury. We then directly targeted NET components with a histone blocking antibody and DNase1, both of which protected mice from TRALI. These data suggest that NETs contribute to lung endothelial injury and that targeting NET formation may be a promising new direction for the treatment of acute lung injury.

Authors

Axelle Caudrillier, Kai Kessenbrock, Brian M. Gilliss, John X. Nguyen, Marisa B. Marques, Marc Monestier, Pearl Toy, Zena Werb, Mark R. Looney

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Figure 2

NET formation is dependent on thromboxane production and MEK signaling and increases endothelial permeability.

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NET formation is dependent on thromboxane production and MEK signaling a...
(A) Quantification of NET release in cell supernatant (MPO-DNA ELISA). Neutrophils were pretreated with the MEK inhibitor (U0126, 10 μM) or a thromboxane receptor antagonist (SQ29548, 10 μM) for 10 minutes before the addition of platelets and TRAP. Pretreatment of neutrophils with U0126 or SQ29548 inhibited NET formation compared with that in neutrophils treated with TRAP-activated platelets. Mean ± SD (n = 6); *P < 0.05, ***P < 0.001 versus media and platelets; †P < 0.05 versus TRAP-activated platelets. (B–D) Representative images from direct immunofluorescence staining of DNA (blue), histone (red), and MPO (green), showing NET formation in neutrophils treated with (B) TRAP-activated platelets and less NET formation in neutrophils pretreated with (C) U0126 or (D) SQ29548. n > 6; Scale bar: 10 μm. (E) Permeability of endothelial cell monolayers (HUVEC) measured in a Transwell system. In selected experiments, HUVECs were primed with LPS (2 μg/ml) for 24 hours prior to the experiment. Permeability was measured by 125I-albumin flux across endothelium over 1 hour and was increased in cells treated with cytomix (0.5 ng/ml) or in LPS-primed endothelium with TRAP-activated platelets or PMA. Mean ± SD (n = 12); *P < 0.05, **P < 0.01, ***P < 0.001 versus HUVECs without treatment. †P < 0.05, †††P < 0.001 versus HUVECs treated LPS and with neutrophils and TRAP-activated platelets.