Activated factor XI increases the procoagulant activity of the extrinsic pathway by inactivating tissue factor pathway inhibitor

Cristina Puy, Erik I. Tucker, Anton Matafonov, Qiufang Cheng, Keith D. Zientek, Dave Gailani, András Gruber, Owen J T McCarty

    Research output: Contribution to journalArticle

    30 Citations (Scopus)

    Abstract

    Activation of coagulation factor XI (FXI) may play a role in hemostasis. The primary substrate of activated FXI (FXIa) is FIX, leading to FX activation (FXa) and thrombin generation. However, recent studies suggest the hemostatic role of FXI may not be restricted to the activation of FIX. We explored whether FXI could interact with and inhibit the activity of tissue factor pathway inhibitor (TFPI). TFPI is an essential reversible inhibitor of activated factor X (FXa) and also inhibits the FVIIa-TF complex. We found that FXIa neutralized both endothelium- and platelet-derived TFPI by cleaving the protein between the Kunitz (K) 1 and K2 domains (Lys86/Thr87) and at the active sites of the K2 (Arg107/Gly108) and K3 (Arg199/Ala200) domains. Addition of FXIa to plasma was able to reverse the ability of TFPI to prolong TF-initiated clotting times in FXI- or FIX-deficient plasma, as well as FXa-initiated clotting times in FX-deficient plasma. Treatment of cultured endothelial cells with FXIa increased the generation of FXa and promoted TF-dependent fibrin formation in recalcified plasma. Together, these results suggest that the hemostatic role of FXIa may be attributed not only to activation of FIX but also to promoting the extrinsic pathway of thrombin generation through inactivation of TFPI.

    Original languageEnglish
    Pages (from-to)1488-1496
    Number of pages9
    JournalBlood
    Volume125
    Issue number9
    DOIs
    Publication statusPublished - 26 Feb 2015

    ASJC Scopus subject areas

    • Medicine(all)

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  • Cite this

    Puy, C., Tucker, E. I., Matafonov, A., Cheng, Q., Zientek, K. D., Gailani, D., Gruber, A., & McCarty, O. J. T. (2015). Activated factor XI increases the procoagulant activity of the extrinsic pathway by inactivating tissue factor pathway inhibitor. Blood, 125(9), 1488-1496. https://doi.org/10.1182/blood-2014-10-604587