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Ramadas N, Lowder K, Dutton J, Trebak F, Faes C, Griffin JH, Pawlinski R, Mosnier LO, Sparkenbaugh E. Biased agonism of protease-activated receptor-1 regulates thromboinflammation in murine sickle cell disease. Blood Adv 2024; 8:3272-3283. [PMID: 38640339 PMCID: PMC11226968 DOI: 10.1182/bloodadvances.2023011907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 03/21/2024] [Accepted: 04/08/2024] [Indexed: 04/21/2024] Open
Abstract
ABSTRACT Sickle cell disease (SCD) is a hereditary hemoglobinopathy marked by hemolytic anemia and vaso-occlusive events (VOEs). Chronic endothelial activation, inflammation, and coagulation activation contribute to vascular congestion, VOEs, and end-organ damage. Coagulation proteases such as thrombin and activated protein C (APC) modulate inflammation and endothelial dysfunction by activating protease-activated receptor 1 (PAR1), a G-protein-coupled receptor. Thrombin cleaves PAR1 at Arg41, while APC cleaves PAR1 at Arg46, initiating either proinflammatory or cytoprotective signaling, respectively, a signaling conundrum known as biased agonism. Our prior research established the role of thrombin and PAR1 in vascular stasis in an SCD mouse model. However, the role of APC and APC-biased PAR1 signaling in thrombin generation, inflammation, and endothelial activation in SCD remains unexplored. Inhibition of APC in SCD mice increased thrombin generation, inflammation, and endothelial activation during both steady state and tumor necrosis factor α challenge. To dissect the individual contributions of thrombin-PAR1 and APC-PAR1 signaling, we used transgenic mice with point mutations at 2 PAR1 cleavage sites, ArgR41Gln (R41Q) imparting insensitivity to thrombin and Arg46Gln (R46Q) imparting insensitivity to APC. Sickle bone marrow chimeras expressing PAR1-R41Q exhibited reduced thrombo-inflammatory responses compared with wild type PAR1 or PAR1-R46Q mice. These findings highlight the potential benefit of reducing thrombin-dependent PAR1 activation while preserving APC-PAR1 signaling in SCD thromboinflammation. These results also suggest that pharmacological strategies promoting biased PAR1 signaling could effectively mitigate vascular complications associated with SCD.
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Affiliation(s)
- Nirupama Ramadas
- Division of Hematology, Department of Medicine, Blood Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Kailyn Lowder
- Division of Hematology, Department of Medicine, Blood Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Joshua Dutton
- Division of Hematology, Department of Medicine, Blood Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Fatima Trebak
- Division of Hematology, Department of Medicine, Blood Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Camille Faes
- Division of Hematology, Department of Medicine, Blood Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - John H. Griffin
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA
| | - Rafal Pawlinski
- Division of Hematology, Department of Medicine, Blood Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Laurent O. Mosnier
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA
| | - Erica Sparkenbaugh
- Division of Hematology, Department of Medicine, Blood Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC
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An engineered factor Va prevents bleeding induced by direct-acting oral anticoagulants by different mechanisms. Blood Adv 2020; 4:3716-3727. [PMID: 32777068 PMCID: PMC7422119 DOI: 10.1182/bloodadvances.2020001699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 06/29/2020] [Indexed: 11/20/2022] Open
Abstract
Control of bleeding with direct-acting oral anticoagulants (DOACs) remains an unmet clinical need. Activated superFactor V (superFVa) is an engineered activated protein C (APC)-resistant FVa variant with enhanced procoagulant activity resulting from an A2/A3 domain disulfide bond and was studied here for control of DOAC-induced bleeding. SuperFVa reversed bleeding induced by FXa inhibitors (rivaroxaban, apixaban), and the FIIa inhibitor dabigatran in BalbC mice. The blocking anti-protein C and APC [(A)PC] antibody SPC-54 also reduced FXa inhibitor induced bleeding similar to superFVa, whereas dabigatran-induced bleeding was not affected. This indicated that sufficient APC was generated to contribute to bleeding in the presence of FXa inhibitors, but not in the presence of dabigatran, suggesting that mechanisms contributing to bleeding differed for FXa and FIIa inhibitors. Despite different mechanisms contributing to bleeding, superFVa effectively reduced bleeding for all DOACs, indicating the versatility of superFVa's properties that contribute to its universal prohemostatic effects for DOAC associated bleeding. Supported by thrombin generation assays on endothelial cells in normal plasma spiked with DOACs and patient plasma anticoagulated with DOACs, 3 complementary mechanisms were identified by which superFVa achieved DOAC class-independent prohemostatic efficiency. These mechanisms are resistance to inactivation by APC, overcoming the FV activation threshold, and maximizing the efficiency of the prothrombinase complex when the available FXa is increased by FVIIa-based prohemostatics. In summary, it is this versatility of superFVa that delineates it from other prohemostatic agents as a promising class-independent rescue agent in bleeding situations associated with DOACs.
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Physiological cerebrovascular remodeling in response to chronic mild hypoxia: A role for activated protein C. Exp Neurol 2016; 283:396-403. [PMID: 27412766 DOI: 10.1016/j.expneurol.2016.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/13/2016] [Accepted: 07/08/2016] [Indexed: 11/22/2022]
Abstract
Activated protein C (APC) is a serine protease that promotes favorable changes in vascular barrier integrity and post-ischemic angiogenic remodeling in animal models of ischemic stroke, and its efficacy is currently being investigated in clinical ischemic stroke trials. Interestingly, application of sub-clinical chronic mild hypoxia (CMH) (8% O2) also promotes angiogenic remodeling and increased tight junction protein expression, suggestive of enhanced blood-brain barrier (BBB) integrity, though the role of APC in mediating the influence of CMH has not been investigated. To examine this potential link, we studied CMH-induced cerebrovascular remodeling after treating mice with two different reagents: (i) a function-blocking antibody that neutralizes APC activity, and (ii) exogenous recombinant murine APC. While CMH promoted endothelial proliferation, increased vascular density, and upregulated the angiogenic endothelial integrins α5β1 and αvβ3, these events were almost completely abolished by functional blockade of APC. Consistent with these findings, addition of exogenous recombinant APC enhanced CMH-induced endothelial proliferation, expansion of total vascular area and further enhanced the CMH-induced right-shift in vessel size distribution. Taken together, our findings support a key role for APC in mediating physiological remodeling of cerebral blood vessels in response to CMH.
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Martinelli N, Girelli D, Baroni M, Guarini P, Sandri M, Lunghi B, Tosi F, Branchini A, Sartori F, Woodhams B, Bernardi F, Olivieri O. Activated factor VII-antithrombin complex predicts mortality in patients with stable coronary artery disease: a cohort study. J Thromb Haemost 2016; 14:655-66. [PMID: 27061056 DOI: 10.1111/jth.13274] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/12/2016] [Indexed: 01/06/2023]
Abstract
BACKGROUND Plasma concentration of activated factor VII (FVIIa)-antithrombin (AT) complex has been proposed as an indicator of intravascular exposure of tissue factor. OBJECTIVES The aims of this observational study were to evaluate (i) FVIIa-AT plasma concentration in subjects with or without coronary artery disease (CAD) and (ii) its association with mortality in a prospective cohort of patients with CAD. METHODS FVIIa-AT levels were measured by elisa in 686 subjects with (n = 546) or without (n = 140) angiographically proven CAD. Subjects with acute coronary syndromes and those taking anticoagulant drugs at the time of enrollment were excluded. CAD patients were followed for total and cardiovascular mortality. RESULTS There was no difference in FVIIa-AT levels between CAD (84.8 with 95% confidence interval [CI] 80.6-88.2 pmol L(-1) ) and CAD-free subjects (83.9 with 95% CI 76.7-92.8 pmol L(-1) ). Within the CAD population, during a 64-month median follow-up, patients with FVIIa-AT levels higher than the median value at baseline (≥ 79 pmol L(-1) ) had a two-fold greater risk of both total and cardiovascular mortality. Results were confirmed after adjustment for sex, age, the other predictors of mortality (hazard ratio for total mortality: 2.05 with 95% CI 1.22-3.45, hazard ratio for cardiovascular mortality 1.94 with 95% CI 1.01-3.73, with a slight improvement of C-statistic over traditional risk factors), FVIIa levels, drug therapy at discharge, and even patients using all the usual medications for CAD treatment. High FVIIa-AT levels also correlated with increased thrombin generation. CONCLUSIONS This preliminary study suggests that plasma concentration of FVIIa-AT is a thrombophilic marker of total and cardiovascular mortality risk in patients with clinically stable CAD.
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Affiliation(s)
- N Martinelli
- Department of Medicine, University of Verona, Verona, Italy
| | - D Girelli
- Department of Medicine, University of Verona, Verona, Italy
| | - M Baroni
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - P Guarini
- Department of Medicine, University of Verona, Verona, Italy
| | - M Sandri
- Department of Medicine, University of Verona, Verona, Italy
| | - B Lunghi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - F Tosi
- Department of Medicine, University of Verona, Verona, Italy
| | - A Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - F Sartori
- Department of Medicine, University of Verona, Verona, Italy
| | | | - F Bernardi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - O Olivieri
- Department of Medicine, University of Verona, Verona, Italy
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von Drygalski A, Bhat V, Gale AJ, Burnier L, Cramer TJ, Griffin JH, Mosnier LO. An engineered factor Va prevents bleeding induced by anticoagulant wt activated protein C. PLoS One 2014; 9:e104304. [PMID: 25127130 PMCID: PMC4134195 DOI: 10.1371/journal.pone.0104304] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 07/07/2014] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE An increased risk of bleeding is observed in patients receiving activated protein C (APC), which may be a limiting factor for the application of novel APC therapies. Since APC's therapeutic effects often require its cytoprotective activities on cells but not APC's anticoagulant activities, an agent that specifically antagonizes APC's anticoagulant effects but not its cytoprotective effects could provide an effective means to control concerns for risk of bleeding. We hypothesized that superFVa, an engineered activated FVa-variant that restores hemostasis in hemophilia could reduce APC-induced bleeding. APPROACH AND RESULTS SuperFVa was engineered with mutations of the APC cleavage sites (Arg506/306/679Gln) and a disulfide bond (Cys609-Cys1691) between the A2 and A3 domains, which augment its biological activity and cause high resistance to APC. SuperFVa normalized APC-prolonged clotting times and restored APC-suppressed thrombin generation in human and murine plasma at concentrations where wild-type (wt) FVa did not show effects. Following intravenous injection of APC into BALB/c mice, addition to whole blood ex vivo of superFVa but not wt-FVa significantly normalized whole blood clotting. Blood loss following tail clip or liver laceration was significantly reduced when superFVa was administered intravenously to BALB/c mice prior to intravenous APC-treatment. Furthermore, superFVa abolished mortality (∼50%) associated with excessive bleeding following liver laceration in mice treated with APC. CONCLUSIONS Our results provide proof of concept that superFVa is effective in preventing APC-induced bleeding and may provide therapeutic benefits as a prohemostatic agent in various situations where bleeding is a serious risk.
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Affiliation(s)
- Annette von Drygalski
- The Scripps Research Institute, Dept of Molecular and Experimental Medicine, La Jolla, California, United States of America
- University of California San Diego, Dept of Medicine, Div of Hematology/Oncology, San Diego, California, United States of America
| | - Vikas Bhat
- The Scripps Research Institute, Dept of Molecular and Experimental Medicine, La Jolla, California, United States of America
- University of California San Diego, Dept of Medicine, Div of Hematology/Oncology, San Diego, California, United States of America
| | - Andrew J. Gale
- The Scripps Research Institute, Dept of Molecular and Experimental Medicine, La Jolla, California, United States of America
| | - Laurent Burnier
- The Scripps Research Institute, Dept of Molecular and Experimental Medicine, La Jolla, California, United States of America
| | - Thomas J. Cramer
- University of California San Diego, Dept of Medicine, Div of Hematology/Oncology, San Diego, California, United States of America
| | - John H. Griffin
- The Scripps Research Institute, Dept of Molecular and Experimental Medicine, La Jolla, California, United States of America
- University of California San Diego, Dept of Medicine, Div of Hematology/Oncology, San Diego, California, United States of America
| | - Laurent O. Mosnier
- The Scripps Research Institute, Dept of Molecular and Experimental Medicine, La Jolla, California, United States of America
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von Drygalski A, Cramer TJ, Bhat V, Griffin JH, Gale AJ, Mosnier LO. Improved hemostasis in hemophilia mice by means of an engineered factor Va mutant. J Thromb Haemost 2014; 12:363-72. [PMID: 24818532 PMCID: PMC4161283 DOI: 10.1111/jth.12489] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 12/02/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND Factor (F)VIIa-based bypassing not always provides sufficient hemostasis in hemophilia. OBJECTIVES To investigate the potential of engineered activated factor V (FVa) variants as bypassing agents in hemophilia A. METHODS Activity of FVa variants was studied in vitro using prothrombinase assays with purified components and in FV- and FVIII-deficient plasma using clotting and thrombin generation assays. In vivo bleed reduction after the tail clip was studied in hemophilia A mice. RESULTS AND CONCLUSIONS FVa mutations included a disulfide bond connecting the A2 and A3 domains and ones that rendered FVa resistant to inactivation by activated protein C (APC). '(super) FVa,' a combination of the A2-A3 disulfide (A2-SS-A3) to stabilize FVa and of APC-cleavage site mutations (Arg506/306/679Gln), had enhanced specific activity and complete APC resistance compared with wild-type FVa, FVL eiden (Arg506Gln), or FVaL eiden (A2-SS-A3). Furthermore, (super) FVa potently increased thrombin generation in vitro in FVIII-deficient plasma. In vivo, (super) FVa reduced bleeding in FVIII-deficient mice more effectively than wild-type FVa. Low-dose (super) FVa, but not wild-type FVa, decreased early blood loss during the first 10 min by more than two-fold compared with saline and provided bleed protection for the majority of mice, similar to treatments with FVIII. During the second 10 min after tail cut, (super) FVa at high dose, but not wild-type FVa, effectively reduced bleeding. These findings suggest that (super) FVa enhances not only clot formation but also clot stabilization. Thus, (super) FVa efficiently improved hemostasis in hemophilia in vitro and in vivo and may have potential therapeutic benefits as a novel bypassing agent in hemophilia.
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Affiliation(s)
- A von Drygalski
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA; Division of Hematology/Oncology, Department of Medicine, University California San Diego, San Diego, CA, USA
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