Despite a wealth of structural and biochemical Information on the TF Initiation complex, we still have an Incomplete understanding of the molecular and cellular mechanisms that control TF's hemostatic and thrombotic activities in vivo. During the previous funding period, our studies were focused on the activation of cell surface TF procoagulant activity (TF decryption) and we identified novel players that are connected by the common thread of regulating the generation of TF* micro particles (MP). Our data show that protein disulfide isomerase (PDl) and integrin pi regulate not only the cell surface procoagulant activity of TF, but also the release of TF* MP, specifically from primary cells that significantiy contribute to TF-dependent thrombus formation in vivo. Furthermore, PAR2 signaling controls the TF load of integrin pi* MP, Indicating an amplification loop to increase the prothrombofic activity of MP. The activation ofthe P2X7 receptor decrypts TF on myeloid cells. Unexpectedly, we found that P2X7 also mediates TF activation and the release of TF* MP from smooth muscle cells. Importantly, P2X7-/- and PAR2-/- mice display abnormal thrombus formation and are protected from vascular thrombosis. Together, these data support the novel concept that TF's prothrombotic activity Is under the control of cell signaling events that feed Into pathways relevant for the generation of TF* MP. The continuation of this project will expand on this new dimension of TF thrombogenicity and pursue new concepts that are highly synergistic with the overall goals of this PPG to understand the complex interactions of vessel wall and blood components In thrombus formation and atherothrombosis.
In Aim 1, we will test the overall hypothesis that integrin pi and PAR2 signaling controls TF procoagulant activity through trafficking and internalization. In vivo, we will determine how deregulation of these signaling pathways on vessel wall cells or in the hematopoietic compartment promotes thrombosis.
In Aim 2, we will study the role ofthe P2X7 receptor In vessel wall and myeloid cells and will test the overall hypothesis that P2X7 signaling is crucial for vascular thrombosis and atherothrombosis by regulating the decryption of TF and the release of TF* MP.

Public Health Relevance

The proposed experiments will elucidate the function of novel players and regulatory cellular circuits In TF- dependent thrombosis and will begin to explore the potential therapeutic benefit of specifically targeting cell signaling pathways to safely attenuate TF thrombogenicity in cardiovascular diseases.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Program Projects (P01)
Project #
Application #
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Scripps Research Institute
La Jolla
United States
Zip Code
Subramaniam, Saravanan; Jurk, Kerstin; Hobohm, Lukas et al. (2017) Distinct contributions of complement factors to platelet activation and fibrin formation in venous thrombus development. Blood 129:2291-2302
Kamikubo, Yuichi; Mendolicchio, G Loredana; Zampolli, Antonella et al. (2017) Selective factor VIII activation by the tissue factor-factor VIIa-factor Xa complex. Blood 130:1661-1670
Amar, Arun Paul; Sagare, Abhay P; Zhao, Zhen et al. (2017) Can adjunctive therapies augment the efficacy of endovascular thrombolysis? A potential role for activated protein C. Neuropharmacology :
Klann, Jane E; Remedios, Kelly A; Kim, Stephanie H et al. (2017) Talin Plays a Critical Role in the Maintenance of the Regulatory T Cell Pool. J Immunol 198:4639-4651
Rothmeier, Andrea S; Marchese, Patrizia; Langer, Florian et al. (2017) Tissue Factor Prothrombotic Activity Is Regulated by Integrin-arf6 Trafficking. Arterioscler Thromb Vasc Biol 37:1323-1331
Deguchi, Hiroshi; Navarro, Silvia; Payne, Amanda B et al. (2017) Low level of the plasma sphingolipid, glucosylceramide, is associated with thrombotic diseases. Res Pract Thromb Haemost 1:33-40
Alsultan, Abdulrahman; Gale, Andrew J; Kurban, Kadijah et al. (2016) Activation-resistant homozygous protein C R229W mutation causing familial perinatal intracranial hemorrhage and delayed onset of thrombosis. Thromb Res 143:17-21
Ruf, Wolfram; Rothmeier, Andrea S; Graf, Claudine (2016) Targeting clotting proteins in cancer therapy - progress and challenges. Thromb Res 140 Suppl 1:S1-7
Bhat, Vikas; von Drygalski, Annette; Gale, Andrew J et al. (2016) Improved coagulation and haemostasis in haemophilia with inhibitors by combinations of superFactor Va and Factor VIIa. Thromb Haemost 115:551-61
Abplanalp, Wesley T; Conklin, Daniel J; Cantor, Joseph M et al. (2016) Enhanced Integrin ?4?1-Mediated Adhesion Contributes to a Mobilization Defect of Endothelial Progenitor Cells in Diabetes. Diabetes 65:3505-3515

Showing the most recent 10 out of 422 publications