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Factor VII a‐induced interaction with integrin controls the release of tissue factor on extracellular vesicles from endothelial cells
Author(s) -
Rothmeier Andrea S.,
Versteeg Henri H.,
Ruf Wolfram
Publication year - 2019
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/jth.14406
Subject(s) - tissue factor , microbiology and biotechnology , integrin , chemistry , thromboplastin , receptor , endothelial stem cell , coagulation , biology , biochemistry , in vitro , medicine
Essentials Prothrombotic extracellular vesicles (EV) carry agonist pathway‐specific proteomes Agonists for protease activated receptor (PAR) 2 signaling have distinct effects on EV composition PAR2 signaling rapidly generates prothrombotic EV and slowly EV with inactive tissue factor (TF) FVIIa integrin ligation restricts TF incorporation into EV from endothelial cellsSummary Background Cell injury signal‐induced activation and release of tissue factor ( TF ) on extracellular vesicles ( EV s) from immune and vessel wall cells propagate local and systemic coagulation initiation. TF trafficking and release on EV s occurs in concert with the release of cell adhesion receptors, including integrin β 1 heterodimers, which control trafficking of the TF –activated factor VII ( FVII a) complex. Activation of the TF signaling partner, protease‐activated receptor ( PAR ) 2, also triggers TF release on integrin β 1 + EV s from endothelial cells, but the physiological signals for PAR 2‐dependent EV generation at the vascular interface remain unknown. Objective To define relevant protease ligands of TF contributing to PAR 2‐dependent release on EV s from endothelial cells. Methods In endothelial cells with balanced expression of TF and PAR 2, we evaluated TF release on EV s by using a combination of activity and antigen assays, immunocapture, and confocal imaging. Results and Conclusions PAR 2 stimulation generated time‐dependent release of distinct TF + EV s with high coagulant activity (early) and high antigen levels (late). Whereas PAR 2 agonist peptide and a stabilized TF – FVII a–activated FX complex triggered TF + EV release, stimulation with FVII a alone promoted cellular retention of TF , despite comparable PAR 2 activation. On endothelial cells, FVII a uniquely induced formation of a complex of TF with integrin α 5 β 1 . Internalization of TF by FVII a or anti‐ TF and activating antibodies against integrin β 1 prevented PAR 2 agonist‐induced release of TF on EV s. These data demonstrate that intracellular trafficking controlled by FVII a forcing interaction with integrin β 1 regulates TF availability for release on procoagulant EV s.