PB0799 - Extracellular vesicles from activated platelets possess a shift in their biochemical profile and enhance the activity of the prothrombinase complex

Monday, June 26, 2023

18:30 – 19:30 ET

Room: Exhibition

Co-Author(s)

Eduara Guerreiro, MSc, PhD

Postdoc
Thrombosis Research Group (TREC), Institute of Clinical Medicine, UiT - The Arctic University of Norway, Tromsø, Norway
Tromsø, Troms, Norway
SK

Sergei Kruglik

Researcher
Laboratoire Jean Perrin, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS, 75005 Paris, France
Paris, Ile-de-France, France
SS

Samantha Swamy

PhD student
Thrombosis Research Group (TREC), Institute of Clinical Medicine, UiT - The Arctic University of Norway, Tromsø, Norway
Tromsø, Troms, Norway
NL

Nadezhda Latysheva

Researcher
Thrombosis Research Group (TREC), Department of Clinical Medicine, UiT – The Arctic University of Norway, Tromsø, Norway
Tromsø, Troms, Norway
B�

Bjarne Østerud

Professor
Thrombosis Research Group (TREC), Institute of Clinical Medicine, UiT - The Arctic University of Norway, Tromsø, Norway
Tromsø, Troms, Norway
AK

Andrey N. Kuzmin

Researcher
Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA
Buffalo, New York, United States
OH

Olav Gaute Hellesø

Professor
Department of Physics and Technology, UiT- The Arctic University of Norway, Tromsø, Norway
Tromsø, Troms, Norway
JH

John-Bjarne Hansen, MD, PhD

Professor
Thrombosis Research Center (TREC), Division of Internal Medicine, University Hospital of North Norway, Tromsø, Norway
Tromsø, Troms, Norway

Presenting Author(s)

Omri Snir, PhD

Researcher
Thrombosis Research Group (TREC), Department of Clinical Medicine, UiT – The Arctic University of Norway, Tromsø, Norway
Tromsø, Troms, Norway

Background: Platelet activation has a role in venous thromboembolism (VTE). Platelet reactivity, assessed by mean platelet volume, is a risk for incident VTE; aspirin reduces the risk of VTE recurrence. Extracellular vesicle (EVs) released from platelets are thought to have a role in coagulation and were reported to have a procoagulant activity that is 50-100-fold higher than platelets. It is however unclear whether platelet activation affects the biochemical composition and procoagulant activity of platelet-EVs.

Aims: To compare the biochemical load and procoagulant activity of EVs isolated from unstimulated (control) and stimulated platelets.

Methods: Platelets were isolated and stimulated with thrombin receptor activator peptide-6 (TRAP-6), or left untouched, i.e., time matched control. Next, the biochemical profile of EVs from control and stimulated platelets was analyzed using Raman spectroscopy at the single-EVs level, as well as their procoagulant activity and protein content.

Results: Analysis of Raman spectra revealed three subsets of platelet-EVs: (i) protein-rich, (ii) protein/lipid-rich, and (iii) lipid-rich. EVs from control platelets were heterogeneous, with protein-rich EVs being the major subset (58.7±3.5%). In contrast, EVs from activated platelets were found predominantly within the dominant protein/lipids-rich subset (>85%). EVs from activated platelets shortened plasma coagulation time by -34.6±10.0% and accelerated the activity of the prothrombinase complex by >6 fold. In comparison EVs from unstimulated platelets reduced plasma coagulation time by -18.6±13.9% and had a minor effect on the prothrombinase complex. A proteomic analysis showed that EVs from activated platelets were enriched with key procoagulant and proinflammatory factors, such as vWF, Multimerin, Cofilin, CCL5 and MIF, as well as platelet activation markers such as CD62P and CD63.

Conclusion(s): Platelet activation induces changes in the biomolecular profile of EVs, resulting in an increased prothrombinase activity and subsequent thrombin generation. This mechanism provides explanation to the association between platelet activation and VTE risk.