Science and Research

Neutrophil-Derived Extracellular Vesicles Activate Platelets after Pneumolysin Exposure

Pneumolysin (PLY) is a pore-forming toxin of Streptococcus pneumoniae that contributes substantially to the inflammatory processes underlying pneumococcal pneumonia and lung injury. Host responses against S. pneumoniae are regulated in part by neutrophils and platelets, both individually and in cooperative interaction. Previous studies have shown that PLY can target both neutrophils and platelets, however, the mechanisms by which PLY directly affects these cells and alters their interactions are not completely understood. In this study, we characterize the effects of PLY on neutrophils and platelets and explore the mechanisms by which PLY may induce neutrophil-platelet interactions. In vitro studies demonstrated that PLY causes the formation of neutrophil extracellular traps (NETs) and the release of extracellular vesicles (EVs) from both human and murine neutrophils. In vivo, neutrophil EV (nEV) levels were increased in mice infected with S. pneumoniae. In platelets, treatment with PLY induced the cell surface expression of P-selectin (CD62P) and binding to annexin V and caused a significant release of platelet EVs (pl-EVs). Moreover, PLY-induced nEVs but not NETs promoted platelet activation. The pretreatment of nEVs with proteinase K inhibited platelet activation, indicating that the surface proteins of nEVs play a role in this process. Our findings demonstrate that PLY activates neutrophils and platelets to release EVs and support an important role for neutrophil EVs in modulating platelet functions in pneumococcal infections.

  • Letsiou, E.
  • Teixeira Alves, L. G.
  • Felten, M.
  • Mitchell, T. J.
  • Müller-Redetzky, H. C.
  • Dudek, S. M.
  • Witzenrath, M.

Keywords

  • Animals
  • Bacterial Proteins/pharmacology
  • Blood Platelets/drug effects/metabolism
  • Extracellular Traps/drug effects/metabolism
  • Extracellular Vesicles/*metabolism
  • Humans
  • Mice
  • Neutrophil Activation/drug effects
  • Neutrophils/*metabolism
  • Platelet Activation/*drug effects
  • Streptolysins/*pharmacology
  • *NETs
  • *Streptococcus pneumoniae
  • *lung injury
  • *microvesicles
  • *pneumonia
Publication details
DOI: 10.3390/cells10123581
Journal: Cells
Number: 12
Work Type: Original
Location: UGMLC
Disease Area: PALI
Partner / Member: JLU
Access-Number: 34944089

DZL Engagements

chevron-down