Directed transport of neutrophil-derived extracellular vesicles enables platelet-mediated innate immune response

Nat Commun. 2016 Nov 15:7:13464. doi: 10.1038/ncomms13464.

Abstract

The innate immune response to bacterial infections requires the interaction of neutrophils and platelets. Here, we show that a multistep reciprocal crosstalk exists between these two cell types, ultimately facilitating neutrophil influx into the lung to eliminate infections. Activated platelets adhere to intravascular neutrophils through P-selectin/P-selectin glycoprotein ligand-1 (PSGL-1)-mediated binding, a primary interaction that allows platelets glycoprotein Ibα (GPIbα)-induced generation of neutrophil-derived extracellular vesicles (EV). EV production is directed by exocytosis and allows shuttling of arachidonic acid into platelets. EVs are then specifically internalized into platelets in a Mac1-dependent fashion, and relocated into intracellular compartments enriched in cyclooxygenase1 (Cox1), an enzyme processing arachidonic acid to synthesize thromboxane A2 (TxA2). Finally, platelet-derived-TxA2 elicits a full neutrophil response by inducing the endothelial expression of ICAM-1, intravascular crawling, and extravasation. We conclude that critical substrate-enzyme pairs are compartmentalized in neutrophils and platelets during steady state limiting non-specific inflammation, but bacterial infection triggers regulated EV shuttling resulting in robust inflammation and pathogen clearance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport / immunology
  • Blood Platelets / immunology*
  • Blood Platelets / metabolism
  • Cyclooxygenase 1 / genetics
  • Cyclooxygenase 1 / immunology
  • Cyclooxygenase 1 / metabolism
  • Escherichia coli Infections / genetics
  • Escherichia coli Infections / immunology
  • Escherichia coli Infections / metabolism
  • Extracellular Vesicles / immunology*
  • Extracellular Vesicles / metabolism
  • Immunity / immunology*
  • Male
  • Membrane Glycoproteins / immunology
  • Membrane Glycoproteins / metabolism
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neutrophils / immunology*
  • Neutrophils / metabolism
  • P-Selectin / immunology
  • P-Selectin / metabolism
  • Platelet Adhesiveness / immunology
  • Platelet Glycoprotein GPIb-IX Complex / immunology
  • Platelet Glycoprotein GPIb-IX Complex / metabolism
  • Pneumonia, Bacterial / genetics
  • Pneumonia, Bacterial / immunology
  • Pneumonia, Bacterial / metabolism
  • Thromboxane A2 / immunology
  • Thromboxane A2 / metabolism

Substances

  • Membrane Glycoproteins
  • P-Selectin
  • P-selectin ligand protein
  • Platelet Glycoprotein GPIb-IX Complex
  • Thromboxane A2
  • Cyclooxygenase 1