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Activity of Tissue Factor in Microparticles Produced in vitro by Endothelial Cells, Monocytes, Granulocytes, and

S G Khaspekova1, O A Antonova, O N Shustova

  • 1Russian Cardiology Research and Production Complex, Russian Ministry of Health, Moscow, 121552, Russia. avmazurov@list.ru.

Biochemistry. Biokhimiia
|June 5, 2016
PubMed

Insights

Tissue factor (TF) activity was investigated in microparticles (MPs) from various cells. Active TF was found in MPs from endothelial cells, monocytes, and THP-1 cells, but not granulocytes or platelets.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Hematology

Background:

  • Membrane microparticles (MPs) are released from activated cells and play roles in hemostasis.
  • Tissue factor (TF) is a key initiator of the extrinsic coagulation pathway.
  • The TF content and activity in MPs from different cell types require further elucidation.

Purpose of the Study:

  • To investigate the presence and activity of TF in MPs derived from various blood and endothelial cells.
  • To determine if TF in MPs contributes to coagulation initiation.
  • To differentiate TF activity based on the cellular origin of MPs.

Main Methods:

  • MPs were generated in vitro from activated endothelial cells (ECs), monocytes, THP-1 cells, granulocytes, and platelets.
  • MP-associated coagulation activity was assessed using a modified recalcification assay.
  • TF-specific blocking antibodies were used to confirm TF's role in coagulation.
  • TF activity was quantified by measuring Factor X activation.

Main Results:

  • MPs from all investigated cell types accelerated plasma coagulation.
  • TF-dependent coagulation acceleration was observed with MPs from ECs, monocytes, and THP-1 cells.
  • MPs from granulocytes and platelets did not exhibit TF-dependent procoagulant activity.
  • Direct measurement confirmed TF activity in MPs from ECs, monocytes, and THP-1 cells, but not from granulocytes or platelets.

Conclusions:

  • Active TF is present in MPs produced by endothelial cells, monocytes, and THP-1 cells.
  • MPs derived from granulocytes and platelets do not contain active TF.
  • These findings highlight the differential contribution of cell-derived MPs to coagulation initiation via TF.

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