Trauma is the leading cause of death in young people worldwide and has an estimated annual healthcare cost of 400 billion dollars per year in the United States alone. Survivors of trauma suffer from severe morbidity in the form of organ failure and thromboembolic complications, which are driven, in large part, by excessive inflammation and a vicious cascade of coagulation abnormalities. The lack of understanding of the mechanisms that regulate inflammation and coagulopathy following trauma present a major international health problem, as the lack of therapeutic targets severely limits the ability to intervene. As such, understanding the link between trauma, inflammation and coagulopathy is the key to developing strategies to help prevent organ failure and morbidity in the millions of annual survivors of trauma. Our lab has recently made great strides towards understanding a potential link. We have identified that signalling through the key innate immune receptor, toll-like receptor 4 (TLR4) on platelets is responsible, in part, for both excessive inflammation and coagulopathy following severe hemorrhage in mice. These findings are a key early advance in the field, as platelets serve as both the initial responders in hemostasis but also as early, key effector cells in the initiation of inflammation. Despite these discoveries, the ligand that triggers this platelet `dysfunction' through TLR4 is unknown. Importantly, severe trauma is known to activate the innate immune system through a release of high quantities of danger associated molecular pattern molecules (DAMPs). The present proposal is based on the hypothesis that high-mobility group box 1 (HMGB1), a key DAMP and well characterized TLR4 ligand, is released specifically by platelets following trauma and regulates both the coagulation abnormalities seen after trauma by paracrine signalling on adjacent platelets at the site of developing thrombus as well as excessive inflammation through signalling to neutrophils and other inflammatory cells. We seek to address 3 key challenges related to this hypothesis. The first involves understanding the mechanisms by which HMGB1 promotes thrombosis through examining effects on key platelet adhesion molecules. The second examines the role of platelet HMGB1 in neutrophil activation and production of neutrophil extracellular traps (NETs) following trauma and the role of platelet-HMGB1 mediated NET production in acute lung injury. Finally, we propose the novel and innovative approach of using a TLR4 inhibitor that we have recently patented (US #9,072.760) and HMGB1 inhibitors packaged into a platelet-mimicking drug delivery nanovector for specific targeting of activated platelets at the site of inflammation and developing thrombus.

Public Health Relevance

Traumatic injury leads to millions of deaths every year and treatments for complications after trauma are limited by a lack of understanding of the cause of the excessive inflammation and abnormal blood clotting seen in this disease. In the proposed studies, we seek to understand the mechanisms of blood clotting and inflammation after trauma by studying two key inflammatory signals on platelets, and we propose a novel and innovative treatment strategy involving the delivery of a new drug directly to platelets using nanotechnology to limit inflammation and regulate blood clotting.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Unknown (R35)
Project #
5R35GM119526-05
Application #
9933936
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Zhao, Xiaoli
Project Start
2016-09-01
Project End
2021-05-31
Budget Start
2020-06-01
Budget End
2021-05-31
Support Year
5
Fiscal Year
2020
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Surgery
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15260
Zhou, Hui; Deng, Meihong; Liu, Yingjie et al. (2018) Platelet HMGB1 is required for efficient bacterial clearance in intra-abdominal bacterial sepsis in mice. Blood Adv 2:638-648
Dyer, Mitchell R; Chen, Qiwei; Haldeman, Shannon et al. (2018) Deep vein thrombosis in mice is regulated by platelet HMGB1 through release of neutrophil-extracellular traps and DNA. Sci Rep 8:2068
Dyer, Mitchell R; Hickman, DaShawn; Luc, Norman et al. (2018) Intravenous administration of synthetic platelets (SynthoPlate) in a mouse liver injury model of uncontrolled hemorrhage improves hemostasis. J Trauma Acute Care Surg 84:917-923
Hickman, DaShawn A; Pawlowski, Christa L; Shevitz, Andrew et al. (2018) Intravenous synthetic platelet (SynthoPlate) nanoconstructs reduce bleeding and improve 'golden hour' survival in a porcine model of traumatic arterial hemorrhage. Sci Rep 8:3118
Boone, Brian A; Murthy, Pranav; Miller-Ocuin, Jennifer et al. (2018) Chloroquine reduces hypercoagulability in pancreatic cancer through inhibition of neutrophil extracellular traps. BMC Cancer 18:678
Dyer, Mitchell; Haldeman, Shannon; Gutierrez, Andres et al. (2017) Uncontrolled Hemorrhagic Shock Modeled via Liver Laceration in Mice with Real Time Hemodynamic Monitoring. J Vis Exp :
Shukla, M; Sekhon, U D S; Betapudi, V et al. (2017) In vitro characterization of SynthoPlate™ (synthetic platelet) technology and its in vivo evaluation in severely thrombocytopenic mice. J Thromb Haemost 15:375-387
von Ungern-Sternberg, Saskia N I; Vogel, Sebastian; Walker-Allgaier, Britta et al. (2017) Extracellular Cyclophilin A Augments Platelet-Dependent Thrombosis and Thromboinflammation. Thromb Haemost 117:2063-2078
Moore, Hunter B; Winfield, Robert D; Aibiki, Mayuki et al. (2017) Is Coagulopathy an Appropriate Therapeutic Target During Critical Illness Such as Trauma or Sepsis? Shock 48:159-167
Vogel, Sebastian; Rath, Dominik; Borst, Oliver et al. (2016) Platelet-derived high-mobility group box 1 promotes recruitment and suppresses apoptosis of monocytes. Biochem Biophys Res Commun 478:143-148