Platelet-Derived Short-Chain Polyphosphates Enhance the Inactivation of Tissue Factor Pathway Inhibitor by Activated Coagulation Factor XI

PLOS ONE, Dec 2019

Introduction Factor (F) XI supports both normal human hemostasis and pathological thrombosis. Activated FXI (FXIa) promotes thrombin generation by enzymatic activation of FXI, FIX, FX, and FV, and inactivation of alpha tissue factor pathway inhibitor (TFPIα), in vitro. Some of these reactions are now known to be enhanced by short-chain polyphosphates (SCP) derived from activated platelets. These SCPs act as a cofactor for the activation of FXI and FV by thrombin and FXIa, respectively. Since SCPs have been shown to inhibit the anticoagulant function of TFPIα, we herein investigated whether SCPs could serve as cofactors for the proteolytic inactivation of TFPIα by FXIa, further promoting the efficiency of the extrinsic pathway of coagulation to generate thrombin. Methods and Results Purified soluble SCP was prepared by size-fractionation of sodium polyphosphate. TFPIα proteolysis was analyzed by western blot. TFPIα activity was measured as inhibition of FX activation and activity in coagulation and chromogenic assays. SCPs significantly accelerated the rate of inactivation of TFPIα by FXIa in both purified systems and in recalcified plasma. Moreover, platelet-derived SCP accelerated the rate of inactivation of platelet-derived TFPIα by FXIa. TFPIα activity was not affected by SCP in recalcified FXI-depleted plasma. Conclusions Our data suggest that SCP is a cofactor for TFPIα inactivation by FXIa, thus, expanding the range of hemostatic FXIa substrates that may be affected by the cofactor functions of platelet-derived SCP.

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Platelet-Derived Short-Chain Polyphosphates Enhance the Inactivation of Tissue Factor Pathway Inhibitor by Activated Coagulation Factor XI

October Platelet-Derived Short-Chain Polyphosphates Enhance the Inactivation of Tissue Factor Pathway Inhibitor by Activated Coagulation Factor XI Cristina Puy 0 1 2 Erik I. Tucker 0 1 2 Ivan S. Ivanov 0 2 David Gailani 0 2 Stephanie A. Smith 0 2 James H. Morrissey 0 2 Andra s Gruber 0 1 2 Owen J. T. McCarty 0 1 2 0 the National Institutes of Health (R01HL101972 , R44HL106919, R01GM116184, R01HL047014). O.J.T. McCarty is an American Heart Association (AHA) Established Investigator (13EIA12630000). C. Puy is an AHA Fellow (14POST18180011). A. Gruber, E.I. Tucker, and Oregon Health & Science University have a significant financial interest in Aronora Inc, a company that may have a commercial interest in the result of this research , USA 1 Departments of Biomedical Engineering Oregon Health & Science University , Portland, Oregon , United States of America, 2 Division of Hematology and Medical Oncology, School of Medicine, Oregon Health & Science University , Portland, Oregon , United States of America , 3 Aronora , Inc , Portland, Oregon , United States of America, 4 Departments of Pathology and Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America, 5 Biochemistry Department, University of Illinois, Urbana, Illinois, United States of America, 6 Department of Cell, Developmental and Cancer Biology Oregon Health & Science University , Portland, Oregon , United States of America 2 Editor: Christian Schulz, Ludwig-Maximilians- Universitat Munchen , GERMANY Factor (F) XI supports both normal human hemostasis and pathological thrombosis. Activated FXI (FXIa) promotes thrombin generation by enzymatic activation of FXI, FIX, FX, and FV, and inactivation of alpha tissue factor pathway inhibitor (TFPIα), in vitro. Some of these reactions are now known to be enhanced by short-chain polyphosphates (SCP) derived from activated platelets. These SCPs act as a cofactor for the activation of FXI and FV by thrombin and FXIa, respectively. Since SCPs have been shown to inhibit the anticoagulant function of TFPIα, we herein investigated whether SCPs could serve as cofactors for the proteolytic inactivation of TFPIα by FXIa, further promoting the efficiency of the extrinsic pathway of coagulation to generate thrombin. rate of inactivation of TFPIα by FXIa in both purified systems and in recalcified plasma. Moreover, platelet-derived SCP accelerated the rate of inactivation of platelet-derived TFPIα by Data Availability Statement; All relevant data are within the paper - OPEN ACCESS FXIa. TFPIα activity was not affected by SCP in recalcified FXI-depleted plasma. Conclusions let-derived SCP. Our data suggest that SCP is a cofactor for TFPIα inactivation by FXIa, thus, expanding the range of hemostatic FXIa substrates that may be affected by the cofactor functions of platebut did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the `author contributions' section. This potential conflict of interest has been reviewed and managed by the Oregon Health & Science University Conflict of Interest in Research Committee. J. Morrissey and S. Smith have a patent: Polyphosphatefunctionalized inorganic nanoparticles as hemostatic compositions and methods of use (9,186,417). These do not alter our adherence to PLOS ONE policies on sharing data and materials. The remaining authors declare no competing financial interests. Competing Interests: A. Gruber, E.I. Tucker, and Oregon Health & Science University have a significant financial interest in Aronora Inc., a company that may have a commercial interest in the results of this research. This potential conflict of interest has been reviewed and managed by the Oregon Health & Science University Conflict of Interest in Research Committee. J. Morrissey and S. Smith have a patent: Polyphosphatefunctionalized inorganic nanoparticles as hemostatic compositions and methods of use (9,186,417). These do not alter our adherence to PLOS ONE policies on sharing data and materials. The remaining authors declare no competing financial interests. Introduction Factor (F) XI was originally described in the waterfall model of coagulation as part of the intrinsic or contact pathway, but it appears to be the only contact factor that contributes to hemostasis. Congenital deficiency of FXI is occasionally associated with trauma-associated abnormal bleeding, especially in tissues with increased fibrinolytic activity [ 1 ]. Since FXII, prekallikrein and high molecular weight kininogen deficiencies do not affect hemostasis, the hemostatic function of FXI may well be manifested through feedback activation by thrombin generated by exposure of blood to tissue factor (TF) [ 2,3 ]. FXIa can also promote thrombin generation through direct activation of FX, FV and FVIII [ 4–6 ]. Additionally, activated platelets release polyp (...truncated)


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Cristina Puy, Erik I. Tucker, Ivan S. Ivanov, David Gailani, Stephanie A. Smith, James H. Morrissey, András Gruber, Owen J. T. McCarty. Platelet-Derived Short-Chain Polyphosphates Enhance the Inactivation of Tissue Factor Pathway Inhibitor by Activated Coagulation Factor XI, PLOS ONE, 2016, Volume 11, Issue 10, DOI: 10.1371/journal.pone.0165172