Tissue factor and plasminogen activator inhibitor type 2 expression in human stimulated monocytes is inhibited by heparin

Guglielmina Pepe, Betti Giusti, Monica Attanasio, Anna Maria Gori, Paolo Comeglio, Francesca Martini, Gianfranco Gensini, Rosanna Abbate, Gian Gastone, Neri Serneri

Research output: Contribution to journalArticlepeer-review


Stimulated monocytes are involved in blood clotting and fibrin dissolution by synthesizing tissue factor (TF) and fibrinolytic components such as plasminogen activator inhibitor type 2 (PAI-2). Heparin interacts with smooth muscle cells, platelets, and endothelial cells and specifically binds to human monocytes. In endothelial and smooth muscle cells, heparin selectively inhibits collagenase and tissue plasminogen activator gene expression. To investigate (1) heparin's influence on the hemostatic system by its interactions with plasma factors and cellular elements and (2) to determine its effects on gene expression in blood circulating cells, we studied the effect of heparin on TF and PAI-2 protein and mRNA in human lipopolysaccharide (LPS)- or interferon-γ (IFN-γ)-stimulated monocytes. TF and PAI-2 proteins were investigated by ELISA and by assaying procoagulant activity. The mRNA study was carried out by an initial PCR screening followed by a Northern blot semiquantitative analysis. Heparin (0.5 U/mL) inhibited both TF and PAI-2 production and gene expression. The contemporaneous protein and mRNA decrease (TF and PAI-2 protein 22 and 42%, respectively; TF and PAI-2 mRNA 23 and 55%, respectively) suggests that this action is, at least partially, at the transcriptional level. The effect is not specific for heparin and is not demonstrated by other glycosaminoglycans (chondroitin-4-sulfate or dermatan sulfate). This action may be relevant for the antithrombotic activity of heparin in cell-mediated blood clotting activation.

Original languageEnglish
Pages (from-to)135-141
Number of pages7
JournalSeminars in Thrombosis and Hemostasis
Issue number2
Publication statusPublished - 1997


  • Glycosaminoglycans
  • Heparin
  • Monocytes
  • Plasminogen activator inhibitor type 2
  • Tissue factor

ASJC Scopus subject areas

  • Hematology


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