This application seeks to improve basic understanding of the molecular mechanisms that mediate cytoprotective actions of coagulation proteases on cells. Available therapeutic solutions for vascular, thrombotic, and inflammatory diseases are limited and mortality rates remain unacceptably high. Activated protein C (APC) has beneficial effects of in a broad spectrum of injury and disease models where ischemia and inflammation contribute to pathogenesis. The cytoprotective activities of APC are responsible for these beneficial effects of APC in vivo and involve the endothelial protein C receptor (EPCR), protease activated receptor (PAR) 1, and PAR3. The cytoprotective effects of APC on cells contrast with proinflammatory effects of other coagulation proteases (e.g. thrombin) on cells and initiated novel perspectives on how the same receptor (PAR1) can mediate such different opposing effects. The EPCR-dependent non-canonical activation of PAR1 at Arg46 and PAR3 at Arg41 are newly discovered mechanisms of biased PAR signaling. The functional selectivity of thrombin versus APC is thus determined by the proteolytic activation sites in PAR1 and PAR3 that give rise to the new N-terminal tethered-ligands. The immediate goal of this application is to gain novel insights into the molecular mechanisms of non-canonical biased PAR signaling and the extent to which the canonical/non-canonical PAR profile determines the functional selectivity of proteases. Major focus will be on structure-function studies of PAR3 non-canonical signaling mechanisms and of PAR canonical/non- canonical proteolysis profiles of coagulation proteases. Furthermore, several conceptual key aspects of the non-canonical PAR activation and biased signaling paradigm will be tested in vitro and in vivo using engineered EPCR variants that are expected to augment cytoprotective mechanisms. The long-term objectives of this application are to contribute to diagnostic and therapeutic progress for vascular, thrombotic, and inflammatory diseases by advancing knowledge through both basic and translational research. Novel hypotheses will be tested using biochemical and cellular biology methods and validated by studies in mouse models in vivo.
The specific aims are: 1) To characterize the structure-activity-function determinants for EPCR- dependent non-canonical PAR1 and PAR3 activation, and 2) To provide proof-of-concept for optimized engineered EPCR variants with improved characteristics. Successful completion of the proposed studies will increase our knowledge and understanding of vascular, thrombotic, and inflammatory diseases and may provide a platform for the development of novel therapeutic strategies for a variety of disorders in which thrombosis, apoptosis and inflammation contribute to pathogenesis.

Public Health Relevance

Vascular, thrombotic, and inflammatory diseases, such as sepsis, heart attack or stroke, will affect most of us at some point in life, with a profound impac on the quality and duration of life thereafter. Available therapeutic solutions are limited and mortality rates remain unacceptably high. Guided by the beneficial cytoprotective effects of activated protein C in a broad range of in vivo injury and disease models, the proposed studies will identify novel molecular mechanisms and investigate novel approaches for potential therapeutic applications using engineered molecular biologics.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
3R01HL104165-06S1
Application #
9268473
Study Section
Program Officer
Warren, Ronald Q
Project Start
2016-05-15
Project End
2016-11-30
Budget Start
2016-05-15
Budget End
2016-11-30
Support Year
6
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
781613492
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Spronk, H M H; Padro, T; Siland, J E et al. (2018) Atherothrombosis and Thromboembolism: Position Paper from the Second Maastricht Consensus Conference on Thrombosis. Thromb Haemost 118:229-250
Griffin, John H; Zlokovic, Berislav V; Mosnier, Laurent O (2018) Activated protein C, protease activated receptor 1, and neuroprotection. Blood 132:159-169
Adams, G N; Sharma, B K; Rosenfeldt, L et al. (2018) Protease-activated receptor-1 impedes prostate and intestinal tumor progression in mice. J Thromb Haemost 16:2258-2269
Wyseure, Tine; Cooke, Esther J; Declerck, Paul J et al. (2018) Defective TAFI activation in hemophilia A mice is a major contributor to joint bleeding. Blood 132:1593-1603
Sinha, Ranjeet K; Wang, Yaoming; Zhao, Zhen et al. (2018) PAR1 biased signaling is required for activated protein C in vivo benefits in sepsis and stroke. Blood 131:1163-1171
Cooke, Esther J; Zhou, Jenny Y; Wyseure, Tine et al. (2018) Vascular Permeability and Remodelling Coincide with Inflammatory and Reparative Processes after Joint Bleeding in Factor VIII-Deficient Mice. Thromb Haemost 118:1036-1047
Mosnier, Laurent O (2018) Warfarin, a juggler's demise. Blood 131:2742-2743
Cooke, Esther J; Zhou, Jenny Y; Wyseure, Tine et al. (2018) Erratum to: Vascular Permeability and Remodelling Coincide with Inflammatory and Reparative Processes after Joint Bleeding in Factor VIII-Deficient Mice. Thromb Haemost :
Fernández, José A; Xu, Xiao; Sinha, Ranjeet K et al. (2017) Activated protein C light chain provides an extended binding surface for its anticoagulant cofactor, protein S. Blood Adv 1:1423-1426
Griffin, John H; Mosnier, Laurent O; Fernández, José A et al. (2016) 2016 Scientific Sessions Sol Sherry Distinguished Lecturer in Thrombosis: Thrombotic Stroke: Neuroprotective Therapy by Recombinant-Activated Protein C. Arterioscler Thromb Vasc Biol 36:2143-2151

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