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Han X, Knauss EA, Fuente MDL, Li W, Conlon RA, LePage DF, Jiang W, Renna SA, McKenzie SE, Nieman MT. A mouse model of the protease-activated receptor 4 Pro310Leu variant has reduced platelet reactivity. J Thromb Haemost 2024; 22:1715-1726. [PMID: 38508397 DOI: 10.1016/j.jtha.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/26/2024] [Accepted: 03/11/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND Protease-activated receptor 4 (PAR4) mediates thrombin signaling on platelets and other cells. Our recent structural studies demonstrated that a single nucleotide polymorphism in extracellular loop 3 and PAR4-P310L (rs2227376) leads to a hyporeactive receptor. OBJECTIVES The goal of this study was to determine how the hyporeactive PAR4 variant in extracellular loop 3 impacts platelet function in vivo using a novel knock-in mouse model (PAR4-322L). METHODS A point mutation was introduced into the PAR4 gene F2rl3 via CRISPR/Cas9 to create PAR4-P322L, the mouse homolog to human PAR4-P310L. Platelet response to PAR4 activation peptide (AYPGKF), thrombin, ADP, and convulxin was monitored by αIIbβ3 integrin activation and P-selectin translocation using flow cytometry or platelet aggregation. In vivo responses were determined by the tail bleeding assay and the ferric chloride-induced carotid artery injury model. RESULTS PAR4-P/L and PAR4-L/L platelets had a reduced response to AYPGKF and thrombin measured by P-selectin translocation or αIIbβ3 activation. The response to ADP and convulxin was unchanged among genotypes. In addition, both PAR4-P/L and PAR4-L/L platelets showed a reduced response to thrombin in aggregation studies. There was an increase in the tail bleeding time for PAR4-L/L mice. The PAR4-P/L and PAR4-L/L mice both showed an extended time to arterial thrombosis. CONCLUSION PAR4-322L significantly reduced platelet responsiveness to AYPGKF and thrombin, which is in agreement with our previous structural and cell signaling studies. In addition, PAR4-322L had prolonged arterial thrombosis time. Our mouse model provides a foundation to further evaluate the role of PAR4 in other pathophysiological contexts.
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Affiliation(s)
- Xu Han
- Case Western Reserve University School of Medicine, Department of Pharmacology, Cleveland, Ohio, USA
| | - Elizabeth A Knauss
- Case Western Reserve University School of Medicine, Department of Pharmacology, Cleveland, Ohio, USA
| | - Maria de la Fuente
- Case Western Reserve University School of Medicine, Department of Pharmacology, Cleveland, Ohio, USA
| | - Wei Li
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine at Marshall University, Huntington, West Virginia, USA
| | - Ronald A Conlon
- Case Transgenic and Targeting Facility, Case Western Reserve University, Cleveland, Ohio, USA
| | - David F LePage
- Case Transgenic and Targeting Facility, Case Western Reserve University, Cleveland, Ohio, USA
| | - Weihong Jiang
- Case Transgenic and Targeting Facility, Case Western Reserve University, Cleveland, Ohio, USA
| | - Stephanie A Renna
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Steven E McKenzie
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Marvin T Nieman
- Case Western Reserve University School of Medicine, Department of Pharmacology, Cleveland, Ohio, USA.
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Han X, Knauss EA, de la Fuente M, Li W, Conlon RA, LePage DF, Jiang W, Renna SA, McKenzie SE, Nieman MT. A Mouse Model of the Protease Activated Receptor 4 (PAR4) Pro310Leu Variant has Reduced Platelet Reactivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.569075. [PMID: 38077081 PMCID: PMC10705540 DOI: 10.1101/2023.12.01.569075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Background Protease activated receptor 4 (PAR4) mediates thrombin signaling on platelets and other cells. Our recent structural studies demonstrated a single nucleotide polymorphism in extracellular loop 3 (ECL3), PAR4-P310L (rs2227376) leads to a hypo-reactive receptor. Objectives The goal of this study was to determine how the hypo-reactive PAR4 variant in ECL3 impacts platelet function in vivo using a novel knock-in mouse model (PAR4-322L). Methods A point mutation was introduced into the PAR4 gene, F2rl3, via CRISPR/Cas9 to create PAR4-P322L, the mouse homolog to human PAR4-P310L. Platelet response to PAR4 activation peptide (AYPGKF), thrombin, ADP, and convulxin was monitored by αIIbβ3 integrin activation and P-selectin translocation using flow cytometry or platelet aggregation. In vivo responses were determined by the tail bleeding assay and the ferric chloride-induced carotid artery injury model. Results PAR4-P/L and PAR4-L/L platelets had a reduced response to AYPGKF and thrombin measured by P-selectin translocation or αIIbβ3 activation. The response to ADP and convulxin was unchanged among genotypes. In addition, both PAR4-P/L and PAR4-L/L platelets showed a reduced response to thrombin in aggregation studies. There was an increase in the tail bleeding time for PAR4-L/L mice. The PAR4-P/L and PAR4-L/L mice both showed an extended time to arterial thrombosis. Conclusions PAR4-322L significantly reduced platelet responsiveness to AYPGKF and thrombin, which is in agreement with our previous structural and cell signaling studies. In addition, PAR4-322L had prolonged arterial thrombosis time. Our mouse model provides a foundation to further evaluate the role of PAR4 in other pathophysiological contexts.
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Affiliation(s)
- Xu Han
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH United States
| | - Elizabeth A. Knauss
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH United States
| | - Maria de la Fuente
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH United States
| | - Wei Li
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine at Marshall University, Huntington, WV United States
| | - Ronald A Conlon
- Case Transgenic and Targeting Facility, Case Western Reserve University, Cleveland, OH United States
| | - David F. LePage
- Case Transgenic and Targeting Facility, Case Western Reserve University, Cleveland, OH United States
| | - Weihong Jiang
- Case Transgenic and Targeting Facility, Case Western Reserve University, Cleveland, OH United States
| | - Stephanie A. Renna
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA United States
| | - Steven E. McKenzie
- Department of Medicine, The Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA United States
| | - Marvin T. Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH United States
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Lee-Rivera I, López E, López-Colomé AM. Diversification of PAR signaling through receptor crosstalk. Cell Mol Biol Lett 2022; 27:77. [PMID: 36088291 PMCID: PMC9463773 DOI: 10.1186/s11658-022-00382-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Protease activated receptors (PARs) are among the first receptors shown to transactivate other receptors: noticeably, these interactions are not limited to members of the same family, but involve receptors as diverse as receptor kinases, prostanoid receptors, purinergic receptors and ionic channels among others. In this review, we will focus on the evidence for PAR interactions with members of their own family, as well as with other types of receptors. We will discuss recent evidence as well as what we consider as emerging areas to explore; from the signalling pathways triggered, to the physiological and pathological relevance of these interactions, since this additional level of molecular cross-talk between receptors and signaling pathways is only beginning to be explored and represents a novel mechanism providing diversity to receptor function and play important roles in physiology and disease.
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Cao D, Strainic MG, Counihan D, Sridar S, An F, Hussain W, Schmaier AH, Nieman M, Medof ME. Vascular Endothelial Cells Produce Coagulation Factors That Control Their Growth via Joint Protease-Activated Receptor and C5a Receptor 1 (CD88) Signaling. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:361-378. [PMID: 35144762 PMCID: PMC8908053 DOI: 10.1016/j.ajpath.2021.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/20/2021] [Accepted: 09/29/2021] [Indexed: 02/03/2023]
Abstract
As per the classical view of the coagulation system, it functions solely in plasma to maintain hemostasis. An experimental approach modeling vascular reconstitution was used to show that vascular endothelial cells (ECs) endogenously synthesize coagulation factors during angiogenesis. Intracellular thrombin generated from this synthesis promotes the mitotic function of vascular endothelial cell growth factor A (VEGF-A). The thrombin concurrently cleaves C5a from EC-synthesized complement component C5 and unmasks the tethered ligand for EC-expressed protease-activated receptor 4 (PAR4). The two ligands jointly trigger EC C5a receptor-1 (C5ar1) and PAR4 signaling, which together promote VEGF receptor 2 growth signaling. C5ar1 is functionally associated with PAR4, enabling C5a or thrombin to elicit Gαi and/or Gαq signaling. EC coagulation factor and EC complement component synthesis concurrently down-regulate with contact inhibition. The connection of these processes with VEGF receptor 2 signaling provides new insights into mechanisms underlying angiogenesis. Knowledge of endogenous coagulation factor/complement component synthesis and joint PAR4/C5ar1 signaling could be applied to other cell types.
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Affiliation(s)
- Devin Cao
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio
| | | | - Daniel Counihan
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Shiva Sridar
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Fengqi An
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Wasim Hussain
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio
| | - Alvin H. Schmaier
- Department of Medicine, University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Marvin Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - M. Edward Medof
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio,Address correspondence to M. Edward Medof, M.D., Ph.D., Institute of Pathology, 2085 Adelbert, Room 301, Cleveland, OH 44106.
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Lucchesi A, Napolitano R, Bochicchio MT, Giordano G, Napolitano M. Platelets Contribution to Thrombin Generation in Philadelphia-Negative Myeloproliferative Neoplasms: The "Circulating Wound" Model. Int J Mol Sci 2021; 22:ijms222111343. [PMID: 34768772 PMCID: PMC8583863 DOI: 10.3390/ijms222111343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/16/2021] [Accepted: 10/18/2021] [Indexed: 12/11/2022] Open
Abstract
Current cytoreductive and antithrombotic strategies in MPNs are mostly based on cell counts and on patient's demographic and clinical history. Despite the numerous studies conducted on platelet function and on the role of plasma factors, an accurate and reliable method to dynamically quantify the hypercoagulability states of these conditions is not yet part of clinical practice. Starting from our experience, and after having sifted through the literature, we propose an in-depth narrative report on the contribution of the clonal platelets of MPNs-rich in tissue factor (TF)-in promoting a perpetual procoagulant mechanism. The whole process results in an unbalanced generation of thrombin and is self-maintained by Protease Activated Receptors (PARs). We chose to define this model as a "circulating wound", as it indisputably links the coagulation, inflammation, and fibrotic progression of the disease, in analogy with what happens in some solid tumours. The platelet contribution to thrombin generation results in triggering a vicious circle supported by the PARs/TGF-beta axis. PAR antagonists could therefore be a good option for target therapy, both to contain the risk of vascular events and to slow the progression of the disease towards end-stage forms. Both the new and old strategies, however, will require tools capable of measuring procoagulant or prohaemorrhagic states in a more extensive and dynamic way to favour a less empirical management of MPNs and their potential clinical complications.
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MESH Headings
- Animals
- Biological Assay
- Blood Platelets/metabolism
- Humans
- Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/drug therapy
- Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/metabolism
- Models, Biological
- Receptors, Fibrinogen/metabolism
- Thrombin/antagonists & inhibitors
- Thrombin/biosynthesis
- Thrombophilia/physiopathology
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Affiliation(s)
- Alessandro Lucchesi
- Hematology Unit, IRCCS Istituto Scientifico Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, 47014 Meldola, Italy;
| | - Roberta Napolitano
- Biosciences Laboratory, IRCCS Istituto Scientifico Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, 47014 Meldola, Italy;
- Correspondence:
| | - Maria Teresa Bochicchio
- Biosciences Laboratory, IRCCS Istituto Scientifico Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, 47014 Meldola, Italy;
| | - Giulio Giordano
- Internal Medicine Division, Hematology Service, Regional Hospital “A. Cardarelli”, 86100 Campobasso, Italy;
| | - Mariasanta Napolitano
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties and Infectious Disease Unit, University Hospital “P. Giaccone”, 90127 Palermo, Italy;
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Bouck EG, de la Fuente M, Zunica ER, Li W, Mumaw MM, Nieman MT. Murine cadherin-6 mediates thrombosis in vivo in a platelet-independent manner. Res Pract Thromb Haemost 2021; 5:125-131. [PMID: 33537536 PMCID: PMC7845066 DOI: 10.1002/rth2.12458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 10/26/2020] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Platelet adhesion is the critical process mediating stable thrombus formation. Previous reports of cadherin-6 on human platelets have demonstrated its role in platelet aggregation and thrombus formation. OBJECTIVES We aimed to further characterize the importance of cadherin-6 in thrombosis in vivo. METHODS Cadherin-6 platelet expression was evaluated by western blotting, flow cytometry, and immunoprecipitation. Thrombosis was evaluated using the FeCl3 and Rose Bengal carotid artery models in C57Bl6 mice treated with anti-cadherin-6 or IgG and wild-type or Cdh6-/- mice. Platelet function was compared in wild-type and Cdh6-/- mice using tail-clip assays, aggregometry, and flow cytometry. RESULTS Human platelet expression of cadherin-6 was confirmed at ~3000 copies per platelet. Cdh6-/- mice or those treated with anti-cadherin-6 antibody showed an increased time to occlusion in both thrombosis models. Cadherin-6 was not expressed on mouse platelets, and there were no differences in tail bleeding times, platelet aggregation, or platelet activation in wild-type versus Cdh6-/- mice. CONCLUSIONS Cadherin-6 plays an essential role in thrombosis in vivo. However, cadherin-6 is not expressed on murine platelets. These data are in contrast to human platelets, which express a functional cadherin-6/catenin complex. The essential, platelet-independent role for cadherin-6 in hemostasis may allow it to be an effective and safe therapeutic target.
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Affiliation(s)
- Emma G. Bouck
- Department of PharmacologyCase Western Reserve UniversityClevelandOHUSA
| | | | | | - Wei Li
- Deparmtent of Biomedical SciencesMarshall University Joan C. Edwards School of MedicineHuntingtonWVUSA
| | - Michele M. Mumaw
- Department of PharmacologyCase Western Reserve UniversityClevelandOHUSA
| | - Marvin T. Nieman
- Department of PharmacologyCase Western Reserve UniversityClevelandOHUSA
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Han X, Hofmann L, de la Fuente M, Alexander N, Palczewski K, Nieman MT. PAR4 activation involves extracellular loop 3 and transmembrane residue Thr153. Blood 2020; 136:2217-2228. [PMID: 32575122 PMCID: PMC7645988 DOI: 10.1182/blood.2019004634] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 05/24/2020] [Indexed: 12/17/2022] Open
Abstract
Protease-activated receptor 4 (PAR4) mediates sustained thrombin signaling in platelets and is required for a stable thrombus. PAR4 is activated by proteolysis of the N terminus to expose a tethered ligand. The structural basis for PAR4 activation and the location of its ligand binding site (LBS) are unknown. Using hydrogen/deuterium exchange (H/D exchange), computational modeling, and signaling studies, we determined the molecular mechanism for tethered ligand-mediated PAR4 activation. H/D exchange identified that the LBS is composed of transmembrane 3 (TM3) domain and TM7. Unbiased computational modeling further predicted an interaction between Gly48 from the tethered ligand and Thr153 from the LBS. Mutating Thr153 significantly decreased PAR4 signaling. H/D exchange and modeling also showed that extracellular loop 3 (ECL3) serves as a gatekeeper for the interaction between the tethered ligand and LBS. A naturally occurring sequence variant (P310L, rs2227376) and 2 experimental mutations (S311A and P312L) determined that the rigidity conferred by prolines in ECL3 are essential for PAR4 activation. Finally, we examined the role of the polymorphism at position 310 in venous thromboembolism (VTE) using the International Network Against Venous Thrombosis (INVENT) consortium multi-ancestry genome-wide association study (GWAS) meta-analysis. Individuals with the PAR4 Leu310 allele had a 15% reduction in relative risk for VTE (odds ratio, 0.85; 95% confidence interval, 0.77-0.94) compared with the Pro310 allele. These data are consistent with our H/D exchange, molecular modeling, and signaling studies. In conclusion, we have uncovered the structural basis for PAR4 activation and identified a previously unrecognized role for PAR4 in VTE.
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Affiliation(s)
- Xu Han
- Case Western Reserve University, School of Medicine, Cleveland, OH; and
| | - Lukas Hofmann
- Case Western Reserve University, School of Medicine, Cleveland, OH; and
| | | | - Nathan Alexander
- Case Western Reserve University, School of Medicine, Cleveland, OH; and
| | | | - Marvin T Nieman
- Case Western Reserve University, School of Medicine, Cleveland, OH; and
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Kahremany S, Hofmann L, Gruzman A, Cohen G. Advances in Understanding the Initial Steps of Pruritoceptive Itch: How the Itch Hits the Switch. Int J Mol Sci 2020; 21:ijms21144883. [PMID: 32664385 PMCID: PMC7402353 DOI: 10.3390/ijms21144883] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 02/07/2023] Open
Abstract
Pruritoceptive (dermal) itch was long considered an accompanying symptom of diseases, a side effect of drug applications, or a temporary sensation induced by invading pruritogens, as produced by the stinging nettle. Due to extensive research in recent years, it was possible to provide detailed insights into the mechanism of itch mediation and modulation. Hence, it became apparent that pruritus is a complex symptom or disease in itself, which requires particular attention to improve patients’ health. Here, we summarize recent findings in pruritoceptive itch, including how this sensation is triggered and modulated by diverse endogenous and exogenous pruritogens and their receptors. A differentiation between mediating pruritogen and modulating pruritogen seems to be of great advantage to understand and decipher the molecular mechanism of itch perception. Only a comprehensive view on itch sensation will provide a solid basis for targeting this long-neglected adverse sensation accompanying numerous diseases and many drug side effects. Finally, we identify critical aspects of itch perception that require future investigation.
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Affiliation(s)
- Shirin Kahremany
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; (L.H.); (A.G.)
- The Skin Research Institute, The Dead Sea and Arava Science Center, Masada 86910, Israel;
- Correspondence:
| | - Lukas Hofmann
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; (L.H.); (A.G.)
| | - Arie Gruzman
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; (L.H.); (A.G.)
| | - Guy Cohen
- The Skin Research Institute, The Dead Sea and Arava Science Center, Masada 86910, Israel;
- Ben-Gurion University of the Negev, Eilat Campus, Eilat 8855630, Israel
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9
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Hwang MS, Strainic MG, Pohlmann E, Kim H, Pluskota E, Ramirez-Bergeron DL, Plow EF, Medof ME. VEGFR2 survival and mitotic signaling depends on joint activation of associated C3ar1/C5ar1 and IL-6R-gp130. J Cell Sci 2019; 132:jcs.219352. [PMID: 30765465 DOI: 10.1242/jcs.219352] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 12/20/2018] [Indexed: 12/17/2022] Open
Abstract
Purified vascular endothelial cell (EC) growth factor receptor-2 (VEGFR2) auto-phosphorylates upon VEGF-A occupation in vitro, arguing that VEGR2 confers its mitotic and viability signaling in and of itself. Herein, we show that, in ECs, VEGFR2 function requires concurrent C3a/C5a receptor (C3ar1/C5ar1) and IL-6 receptor (IL-6R)-gp130 co-signaling. C3ar1/C5ar1 or IL-6R blockade totally abolished VEGFR2 auto-phosphorylation, downstream Src, ERK, AKT, mTOR and STAT3 activation, and EC cell cycle entry. VEGF-A augmented production of C3a/C5a/IL-6 and their receptors via a two-step p-Tyk2/p-STAT3 process. Co-immunoprecipitation analyses, confocal microscopy, ligand pulldown and bioluminescence resonance energy transfer assays all indicated that the four receptors are physically interactive. Angiogenesis in murine day 5 retinas and in adult tissues was accelerated when C3ar1/C5ar1 signaling was potentiated, but repressed when it was disabled. Thus, C3ar1/C5ar1 and IL-6R-gp130 joint activation is needed to enable physiological VEGFR2 function.
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Affiliation(s)
- Ming-Shih Hwang
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Michael G Strainic
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Elliot Pohlmann
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Haesuk Kim
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Elzbieta Pluskota
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland OH 44195, USA
| | - Diana L Ramirez-Bergeron
- Case Cardiovascular Research Institute and University Hospitals, Case Western Reserve University School of Medicine and University Hospitals, Cleveland, Ohio 44106, USA
| | - Edward F Plow
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland OH 44195, USA
| | - M Edward Medof
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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11
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Whitley MJ, Henke D, Ghazi A, Nieman M, Stoller M, Simon LM, Chen E, Vesci J, Holinstat M, McKenzie S, Shaw C, Edelstein L, Bray PF. The protease-activated receptor 4 Ala120Thr variant alters platelet responsiveness to low-dose thrombin and protease-activated receptor 4 desensitization, and is blocked by non-competitive P2Y 12 inhibition. J Thromb Haemost 2018; 16:2501-2514. [PMID: 30347494 PMCID: PMC6289679 DOI: 10.1111/jth.14318] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Indexed: 01/07/2023]
Abstract
Essentials The rs773902 SNP results in differences in platelet protease-activated receptor (PAR4) function. The functional consequences of rs773902 were analyzed in human platelets and stroke patients. rs773902 affects thrombin-induced platelet function, PAR4 desensitization, stroke association. Enhanced PAR4 Thr120 effects on platelet function are blocked by ticagrelor. SUMMARY: Background F2RL3 encodes protease-activated receptor (PAR) 4 and harbors an A/G single-nucleotide polymorphism (SNP) (rs773902) with racially dimorphic allelic frequencies. This SNP mediates an alanine to threonine substitution at residue 120 that alters platelet PAR4 activation by the artificial PAR4-activation peptide (PAR4-AP) AYPGKF. Objectives To determine the functional effects of rs773902 on stimulation by a physiological agonist, thrombin, and on antiplatelet antagonist activity. Methods Healthy human donors were screened and genotyped for rs773902. Platelet function in response to thrombin was assessed without and with antiplatelet antagonists. The association of rs773902 alleles with stroke was assessed in the Stroke Genetics Network study. Results As compared with rs773902 GG donors, platelets from rs773902 AA donors had increased aggregation in response to subnanomolar concentrations of thrombin, increased granule secretion, and decreased sensitivity to PAR4 desensitization. In the presence of PAR1 blockade, this genotype effect was abolished by higher concentrations of or longer exposure to thrombin. We were unable to detect a genotype effect on thrombin-induced PAR4 cleavage, dimerization, and lipid raft localization; however, rs773902 AA platelets required a three-fold higher level of PAR4-AP for receptor desensitization. Ticagrelor, but not vorapaxar, abolished the PAR4 variant effect on thrombin-induced platelet aggregation. A significant association of modest effect was detected between the rs773902 A allele and stroke. Conclusion The F2RL3 rs773902 SNP alters platelet reactivity to thrombin; the allelic effect requires P2Y12 , and is not affected by gender. Ticagrelor blocks the enhanced reactivity of rs773902 A platelets. PAR4 encoded by the rs773902 A allele is relatively resistant to desensitization and may contribute to stroke risk.
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Affiliation(s)
- M. J. Whitley
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - D.M. Henke
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - A. Ghazi
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - M. Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
| | - Michelle Stoller
- Program in Molecular Medicine and the Division of Hematology and Hematologic Malignancies, Department of Internal Medicine, University of Utah, Salt Lake City, UT
| | - L. M. Simon
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - E. Chen
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
| | - J. Vesci
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - M. Holinstat
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - S.E. McKenzie
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - C.A. Shaw
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX
- Department of Statistics, Rice University, Houston, TX
| | - L.C. Edelstein
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA
| | - Paul F. Bray
- Program in Molecular Medicine and the Division of Hematology and Hematologic Malignancies, Department of Internal Medicine, University of Utah, Salt Lake City, UT
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12
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Tricoci P, Neely M, Whitley MJ, Edelstein LC, Simon LM, Shaw C, Fortina P, Moliterno DJ, Armstrong PW, Aylward P, White H, Van de Werf F, Jennings LK, Wallentin L, Held C, Harrington RA, Mahaffey KW, Bray PF. Effects of genetic variation in protease activated receptor 4 after an acute coronary syndrome: Analysis from the TRACER trial. Blood Cells Mol Dis 2018; 72:37-43. [PMID: 30055940 DOI: 10.1016/j.bcmd.2018.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 01/05/2023]
Abstract
Variation in platelet response to thrombin may affect the safety and efficacy of PAR antagonism. The Thr120 variant of the common single nucleotide polymorphism (SNP) rs773902 in the protease-activated receptor (PAR) 4 gene is associated with higher platelet aggregation compared to the Ala120 variant. We investigated the relationship between the rs773902 SNP with major bleeding and ischemic events, safety, and efficacy of PAR1 inhibition in 6177 NSTE ACS patients in the TRACER trial. There was a lower rate of GUSTO moderate/severe bleeding in patients with the Thr120 variant. The difference was driven by a lower rate in the smaller homozygous group (recessive model, HR 0.13 [0.02-0.92] P = 0.042). No significant differences were observed in the ischemic outcomes. The excess in bleeding observed with PAR1 inhibition was attenuated in patients with the Thr120 variant, but the interactions were not statistically significant. In summary, lower major bleeding rates were observed in the overall TRACER cohort with the hyperreactive PAR4 Thr120 variant. The increase in bleeding with vorapaxar was attenuated with the Thr120 variant, but we could not demonstrate an interaction with PAR1 inhibition. These findings warrant further exploration, including those of African ancestry where the A allele (Thr120) frequency is ~65%.
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Affiliation(s)
| | - Megan Neely
- Duke Clinical Research Institute, Duke University, Durham, NC, USA
| | - Michael J Whitley
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Sidney Kimmel Medical College, Philadelphia, PA, USA
| | - Leonard C Edelstein
- The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Sidney Kimmel Medical College, Philadelphia, PA, USA
| | - Lukas M Simon
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Chad Shaw
- Department of Human & Molecular Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Statistics, Rice University, Houston, TX, USA
| | - Paolo Fortina
- Cancer Genomics and Bioinformatics Laboratory, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - David J Moliterno
- Gill Heart Institute and Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY, USA
| | | | - Philip Aylward
- Division of Medicine, Cardiac & Critical Care Services, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Harvey White
- Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand
| | - Frans Van de Werf
- Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Lisa K Jennings
- CirQuest Labs, LLC, and University of Tennessee Health Science Center, Memphis, TN, USA
| | - Lars Wallentin
- Department of Medical Sciences, Uppsala Clinical Research Center, Uppsala, Sweden
| | - Claes Held
- Department of Medical Sciences, Uppsala Clinical Research Center, Uppsala, Sweden
| | | | | | - Paul F Bray
- Division of Hematology and Hematologic Malignancies in the Department of Internal Medicine and the Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA.
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13
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Rwibasira Rudinga G, Khan GJ, Kong Y. Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy. Int J Mol Sci 2018; 19:E573. [PMID: 29443899 PMCID: PMC5855795 DOI: 10.3390/ijms19020573] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/09/2018] [Accepted: 02/09/2018] [Indexed: 12/29/2022] Open
Abstract
Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.
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Affiliation(s)
- Gamariel Rwibasira Rudinga
- School of Life Science & Technology, China Pharmaceutical University, 24 Tong Jia Street, Nanjing 210009, China.
| | - Ghulam Jilany Khan
- Jiangsu Center for Pharmacodynamics Research, Evaluation and Drug Screening, China Pharmaceutical University, Nanjing 210009, China.
| | - Yi Kong
- School of Life Science & Technology, China Pharmaceutical University, 24 Tong Jia Street, Nanjing 210009, China.
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14
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Sharma R, Waller AP, Agrawal S, Wolfgang KJ, Luu H, Shahzad K, Isermann B, Smoyer WE, Nieman MT, Kerlin BA. Thrombin-Induced Podocyte Injury Is Protease-Activated Receptor Dependent. J Am Soc Nephrol 2017; 28:2618-2630. [PMID: 28424276 PMCID: PMC5576925 DOI: 10.1681/asn.2016070789] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 03/16/2017] [Indexed: 12/29/2022] Open
Abstract
Nephrotic syndrome is characterized by massive proteinuria and injury of specialized glomerular epithelial cells called podocytes. Studies have shown that, whereas low-concentration thrombin may be cytoprotective, higher thrombin concentrations may contribute to podocyte injury. We and others have demonstrated that ex vivo plasma thrombin generation is enhanced during nephrosis, suggesting that thrombin may contribute to nephrotic progression. Moreover, nonspecific thrombin inhibition has been shown to decrease proteinuria in nephrotic animal models. We thus hypothesized that thrombin contributes to podocyte injury in a protease-activated receptor-specific manner during nephrosis. Here, we show that specific inhibition of thrombin with hirudin reduced proteinuria in two rat nephrosis models, and thrombin colocalized with a podocyte-specific marker in rat glomeruli. Furthermore, flow cytometry immunophenotyping revealed that rat podocytes express the protease-activated receptor family of coagulation receptors in vivo High-concentration thrombin directly injured conditionally immortalized human and rat podocytes. Using receptor-blocking antibodies and activation peptides, we determined that thrombin-mediated injury depended upon interactions between protease-activated receptor 3 and protease-activated receptor 4 in human podocytes, and between protease-activated receptor 1 and protease-activated receptor 4 in rat podocytes. Proximity ligation and coimmunoprecipitation assays confirmed thrombin-dependent interactions between human protease-activated receptor 3 and protease-activated receptor 4, and between rat protease-activated receptor 1 and protease-activated receptor 4 in cultured podocytes. Collectively, these data implicate thrombinuria as a contributor to podocyte injury during nephrosis, and suggest that thrombin and/or podocyte-expressed thrombin receptors may be novel therapeutic targets for nephrotic syndrome.
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Affiliation(s)
- Ruchika Sharma
- Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital
- Division of Hematology, Oncology, and BMT, and
| | - Amanda P Waller
- Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital
| | - Shipra Agrawal
- Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital
| | - Katelyn J Wolfgang
- Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital
| | - Hiep Luu
- Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital
- Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Khurrum Shahzad
- Institute of Clinical Chemistry and Pathobiochemistry, Otto-von-Guericke University, Magdeburg, Germany
- Department of Biotechnology, University of Sargodha, Sargodha, Pakistan; and
| | - Berend Isermann
- Institute of Clinical Chemistry and Pathobiochemistry, Otto-von-Guericke University, Magdeburg, Germany
| | - William E Smoyer
- Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital
- Division of Nephrology, Nationwide Children's Hospital, Columbus, Ohio
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Marvin T Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio
| | - Bryce A Kerlin
- Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital,
- Division of Hematology, Oncology, and BMT, and
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio
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15
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Norman JE, Cunningham MR, Jones ML, Walker ME, Westbury SK, Sessions RB, Mundell SJ, Mumford AD. Protease-Activated Receptor 4 Variant p.Tyr157Cys Reduces Platelet Functional Responses and Alters Receptor Trafficking. Arterioscler Thromb Vasc Biol 2016; 36:952-60. [DOI: 10.1161/atvbaha.115.307102] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/22/2016] [Indexed: 01/05/2023]
Abstract
Objective—
Protease-activated receptor 4 (PAR4) is a key regulator of platelet reactivity and is encoded by
F2RL3
, which has abundant rare missense variants. We aimed to provide proof of principle that rare
F2LR3
variants potentially affect platelet reactivity and responsiveness to PAR1 antagonist drugs and to explore underlying molecular mechanisms.
Approach and Results—
We identified 6 rare
F2RL3
missense variants in 236 cardiac patients, of which the variant causing a tyrosine 157 to cysteine substitution (Y157C) was predicted computationally to have the greatest effect on PAR4 structure. Y157C platelets from 3 cases showed reduced responses to PAR4-activating peptide and to α-thrombin compared with controls, but no reduction in responses to PAR1-activating peptide. Pretreatment with the PAR1 antagonist vorapaxar caused lower residual α-thrombin responses in Y157C platelets than in controls, indicating greater platelet inhibition. HEK293 cells transfected with a PAR4 Y157C expression construct had reduced PAR4 functional responses, unchanged total PAR4 expression but reduced surface expression. PAR4 Y157C was partially retained in the endoplasmic reticulum and displayed an expression pattern consistent with defective
N
-glycosylation. Mutagenesis of Y322, which is the putative hydrogen bond partner of Y157, also reduced PAR4 surface expression in HEK293 cells.
Conclusions—
Reduced PAR4 responses associated with Y157C result from aberrant anterograde surface receptor trafficking, in part, because of disrupted intramolecular hydrogen bonding. Characterization of PAR4 Y157C establishes that rare
F2RL3
variants have the potential to markedly alter platelet PAR4 reactivity particularly after exposure to therapeutic PAR1 antagonists.
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Affiliation(s)
- Jane E. Norman
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
| | - Margaret R. Cunningham
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
| | - Matthew L. Jones
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
| | - Mary E. Walker
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
| | - Sarah K. Westbury
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
| | - Richard B. Sessions
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
| | - Stuart J. Mundell
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
| | - Andrew D. Mumford
- From the School of Clinical Sciences (J.E.N., M.E.W., S.K.W., A.D.M.), School of Cellular and Molecular Medicine (M.L.J., A.D.M.), School of Biochemistry (R.B.S.), and School of Physiology and Pharmacology (S.J.M.), University of Bristol, Bristol, United Kingdom; and Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom (M.R.C.)
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16
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Abstract
Protease signaling in cells elicits multiple physiologically important responses via protease-activated receptors (PARs). There are 4 members of this family of G-protein-coupled receptors (PAR1-4). PARs are activated by proteolysis of the N terminus to reveal a tethered ligand. The rate-limiting step of PAR signaling is determined by the efficiency of proteolysis of the N terminus, which is regulated by allosteric binding sites, cofactors, membrane localization, and receptor dimerization. This ultimately controls the initiation of PAR signaling. In addition, these factors also control the cellular response by directing signaling toward G-protein or β-arrestin pathways. PAR1 signaling on endothelial cells is controlled by the activating protease and heterodimerization with PAR2 or PAR3. As a consequence, the genetic and epigenetic control of PARs and their cofactors in physiologic and pathophysiologic conditions have the potential to influence cellular behavior. Recent studies have uncovered polymorphisms that result in PAR4 sequence variants with altered reactivity that interact to influence platelet response. This further demonstrates how interactions within the plasma membrane can control the physiological output. Understanding the structural rearrangement following PAR activation and how PARs are allosterically controlled within the plasma membrane will determine how best to target this family of receptors therapeutically. The purpose of this article is to review how signaling from PARs is influenced by alternative cleavage sites and the physical interactions within the membrane. Going forward, it will be important to relate the altered signaling to the molecular arrangement of PARs in the cell membrane and to determine how these may be influenced genetically.
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17
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French SL, Hamilton JR. Protease-activated receptor 4: from structure to function and back again. Br J Pharmacol 2016; 173:2952-65. [PMID: 26844674 DOI: 10.1111/bph.13455] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 01/22/2016] [Accepted: 01/29/2016] [Indexed: 12/21/2022] Open
Abstract
Protease-activated receptors are a family of four GPCRs (PAR1-PAR4) with a number of unique attributes. Nearly two and a half decades after the discovery of the first PAR, an antagonist targeting this receptor has been approved for human use. The first-in-class PAR1 antagonist, vorapaxar, was approved for use in the USA in 2014 for the prevention of thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. These recent developments indicate the clinical potential of manipulating PAR function. While much work has been aimed at uncovering the function of PAR1 and, to a lesser extent, PAR2, comparatively little is known regarding the pharmacology and physiology of PAR3 and PAR4. Recent studies have begun to develop the pharmacological and genetic tools required to study PAR4 function in detail, and there is now emerging evidence for the function of PAR4 in disease settings. In this review, we detail the discovery, structure, pharmacology, physiological significance and therapeutic potential of PAR4. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- Shauna L French
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia
| | - Justin R Hamilton
- Australian Centre for Blood Diseases, Monash University, Melbourne, Australia.
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18
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Holinstat M, Bray PF. Protease receptor antagonism to target blood platelet therapies. Clin Pharmacol Ther 2015; 99:72-81. [PMID: 26501993 DOI: 10.1002/cpt.282] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 01/24/2023]
Abstract
Platelet activation and thrombus formation play a central role in ischemic vascular disease. Thrombin, an especially potent physiologic agonist mediating in vivo activation of platelets, acts via a unique family of G-protein-coupled receptors called protease-activated receptors (PARs) with a broad tissue expression. This review focuses on current antiplatelet therapies as well as innovative approaches to targeting PARs in patients with atherothrombotic vascular disease.
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Affiliation(s)
- M Holinstat
- University of Michigan Medical School, Departments of Pharmacology and Internal Medicine, Ann Arbor, Michigan, USA
| | - P F Bray
- Thomas Jefferson University, The Cardeza Foundation for Hematologic Research and the Department of Medicine, Jefferson Medical College, Philadelphia, Pennsylvania, USA
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19
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Mumaw MM, de la Fuente M, Noble DN, Nieman MT. Targeting the anionic region of human protease-activated receptor 4 inhibits platelet aggregation and thrombosis without interfering with hemostasis. J Thromb Haemost 2014; 12:1331-41. [PMID: 24888424 PMCID: PMC4127092 DOI: 10.1111/jth.12619] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 05/25/2014] [Indexed: 12/23/2022]
Abstract
BACKGROUND Human platelet activation and aggregation is a complex process. To date, many therapies have been developed targeting proteins that mediate this process to prevent unwanted activation. However, the current standard of care for acute coronary syndromes still has limitations, including bleeding risk. OBJECTIVE To evaluate the protease-activated receptor 4 (PAR4) anionic cluster as a viable antiplatelet target by using a polyclonal antibody (CAN12). METHODS We used western blotting, aggregation and secretion ex vivo to evaluate the ability of CAN12 to interact with PAR4 and inhibit platelet activation. The effects of CAN12 in vivo were evaluated with the Rose Bengal arterial thrombosis model and two models of hemostasis. RESULTS CAN12 was able to interact with human PAR4 and delay PAR4 cleavage. In addition, CAN12 inhibited thrombin-induced human platelet aggregation and secretion in a dose-dependent manner. The specificity of CAN12 was agonist-dependent. In vivo, we determined that CAN12 was able to inhibit arterial thrombosis, and, using two independent methods, we found that CAN12 did not influence hemostasis. CONCLUSION Targeting the extracellular anionic cluster on PAR4 is a viable novel strategy as an antiplatelet therapy.
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Affiliation(s)
- M M Mumaw
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
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20
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Arachiche A, de la Fuente M, Nieman MT. Platelet specific promoters are insufficient to express protease activated receptor 1 (PAR1) transgene in mouse platelets. PLoS One 2014; 9:e97724. [PMID: 24830314 PMCID: PMC4022678 DOI: 10.1371/journal.pone.0097724] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/09/2014] [Indexed: 11/18/2022] Open
Abstract
The in vivo study of protease activated receptors (PARs) in platelets is complicated due to species specific expression profiles. Human platelets express PAR1 and PAR4 whereas mouse platelets express PAR3 and PAR4. Further, PAR subtypes interact with one another to influence activation and signaling. The goal of the current study was to generate mice expressing PAR1 on their platelets using transgenic approaches to mimic PAR expression found in human platelets. This system would allow us to examine specific signaling from PAR1 and the PAR1-PAR4 heterodimer in vivo. Our first approach used the mouse GPIbα promoter to drive expression of mouse PAR1 in platelets (GPIbα-Tg-mPAR1). We obtained the expected frequency of founders carrying the transgene and had the expected Mendelian distribution of the transgene in multiple founders. However, we did not observe expression or a functional response of PAR1. As a second approach, we targeted human PAR1 with the same promoter (GPIbα-Tg-hPAR1). Once again we observed the expected frequency and distributing of the transgene. Human PAR1 expression was detected in platelets from the GPIbα-Tg-hPAR1 mice by flow cytometry, however, at a lower level than for human platelets. Despite a low level of PAR1 expression, platelets from the GPIbα-Tg-hPAR1 mice did not respond to the PAR1 agonist peptide (SFLLRN). In addition, they did not respond to thrombin when crossed to the PAR4−/− mice. Finally, we used an alternative platelet specific promoter, human αIIb, to express human PAR1 (αIIb-Tg-hPAR1). Similar to our previous attempts, we obtained the expected number of founders but did not detect PAR1 expression or response in platelets from αIIb-Tg-hPAR1 mice. Although unsuccessful, the experiments described in this report provide a resource for future efforts in generating mice expressing PAR1 on their platelets. We provide an experimental framework and offer considerations that will save time and research funds.
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Affiliation(s)
- Amal Arachiche
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - María de la Fuente
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Marvin T. Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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21
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Sidhu TS, French SL, Hamilton JR. Differential signaling by protease-activated receptors: implications for therapeutic targeting. Int J Mol Sci 2014; 15:6169-83. [PMID: 24733067 PMCID: PMC4013622 DOI: 10.3390/ijms15046169] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/14/2014] [Accepted: 04/03/2014] [Indexed: 12/29/2022] Open
Abstract
Protease-activated receptors (PARs) are a family of four G protein-coupled receptors that exhibit increasingly appreciated differences in signaling and regulation both within and between the receptor class. By nature of their proteolytic self-activation mechanism, PARs have unique processes of receptor activation, "ligand" binding, and desensitization/resensitization. These distinctive aspects have presented both challenges and opportunities in the targeting of PARs for therapeutic benefit-the most notable example of which is inhibition of PAR1 on platelets for the prevention of arterial thrombosis. However, more recent studies have uncovered further distinguishing features of PAR-mediated signaling, revealing mechanisms by which identical proteases elicit distinct effects in the same cell, as well as how distinct proteases produce different cellular consequences via the same receptor. Here we review this differential signaling by PARs, highlight how important distinctions between PAR1 and PAR4 are impacting on the progress of a new class of anti-thrombotic drugs, and discuss how these more recent insights into PAR signaling may present further opportunities for manipulating PAR activation and signaling in the development of novel therapies.
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Affiliation(s)
- Tejminder S Sidhu
- Australian Centre for Blood Diseases & Department of Clinical Haematology, Monash University, Melbourne 3004, Australia.
| | - Shauna L French
- Australian Centre for Blood Diseases & Department of Clinical Haematology, Monash University, Melbourne 3004, Australia.
| | - Justin R Hamilton
- Australian Centre for Blood Diseases & Department of Clinical Haematology, Monash University, Melbourne 3004, Australia.
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22
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Khan A, Li D, Ibrahim S, Smyth E, Woulfe DS. The physical association of the P2Y12 receptor with PAR4 regulates arrestin-mediated Akt activation. Mol Pharmacol 2014; 86:1-11. [PMID: 24723492 DOI: 10.1124/mol.114.091595] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is now well accepted that protease activated receptor (PAR) 1 and PAR4 have differential roles in platelet activation. PAR4, a low-affinity thrombin receptor in human platelets, participates in sustained platelet activation in a P2Y12-dependent manner; however, the mechanisms are not defined. Our previous studies demonstrated that thrombin induces the association of PAR4 with P2Y12, together with arrestin recruitment to the complex. Here we show that PAR4 and P2Y12 directly interact to coregulate Akt signaling after PAR4 activation. We observed direct and specific interaction of P2Y12 with PAR4 but not PAR1 by bioluminescent resonance energy transfer when the receptors were coexpressed in human embryonic kidney 293T cells. PAR4-P2Y12 dimerization was promoted by PAR4-AP and inhibited by P2Y12 antagonist. By using sequence comparison of the transmembrane domains of PAR1 and PAR4, we designed a mutant form of PAR4, "PAR4SFT," by replacing LGL194-196 at the base of transmembrane domain 4 with the corresponding aligned PAR1 residues SFT 220-222. PAR4SFT supported only 8.74% of PAR4-P2Y12 interaction, abolishing P2Y12-dependent arrestin recruitment to PAR4 and Akt activation. Nonetheless, PAR4SFT still supported homodimerization with PAR4. PAR4SFT failed to induce a calcium flux when expressed independently; however, coexpression of increasing concentrations of PAR4SFT, together with PAR4 potentiated PAR4-mediated calcium flux, suggested that PAR4 act as homodimers to signal to Gq-coupled calcium responses. In conclusion, PAR4 LGL (194-196) governs agonist-dependent association of PAR4 with P2Y12 and contributes to Gq-coupled calcium responses. PAR4-P2Y12 association supports arrestin-mediated sustained signaling to Akt. Hence, PAR4-P2Y12 dimerization is likely to be important for the PAR4-P2Y12 dependent stabilization of platelet thrombi.
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Affiliation(s)
- Aasma Khan
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Dongjun Li
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Salam Ibrahim
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Emer Smyth
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
| | - Donna S Woulfe
- Department of Biological Sciences, University of Delaware, Newark, Delaware (A.K., D.L., D.S.W.); and Institute for Translational Medicine and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania (S.I., E.S.)
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Gieseler F, Ungefroren H, Settmacher U, Hollenberg MD, Kaufmann R. Proteinase-activated receptors (PARs) - focus on receptor-receptor-interactions and their physiological and pathophysiological impact. Cell Commun Signal 2013; 11:86. [PMID: 24215724 PMCID: PMC3842752 DOI: 10.1186/1478-811x-11-86] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/25/2013] [Indexed: 02/07/2023] Open
Abstract
Proteinase-activated receptors (PARs) are a subfamily of G protein-coupled receptors (GPCRs) with four members, PAR1, PAR2, PAR3 and PAR4, playing critical functions in hemostasis, thrombosis, embryonic development, wound healing, inflammation and cancer progression. PARs are characterized by a unique activation mechanism involving receptor cleavage by different proteinases at specific sites within the extracellular amino-terminus and the exposure of amino-terminal “tethered ligand“ domains that bind to and activate the cleaved receptors. After activation, the PAR family members are able to stimulate complex intracellular signalling networks via classical G protein-mediated pathways and beta-arrestin signalling. In addition, different receptor crosstalk mechanisms critically contribute to a high diversity of PAR signal transduction and receptor-trafficking processes that result in multiple physiological effects. In this review, we summarize current information about PAR-initiated physical and functional receptor interactions and their physiological and pathological roles. We focus especially on PAR homo- and heterodimerization, transactivation of receptor tyrosine kinases (RTKs) and receptor serine/threonine kinases (RSTKs), communication with other GPCRs, toll-like receptors and NOD-like receptors, ion channel receptors, and on PAR association with cargo receptors. In addition, we discuss the suitability of these receptor interaction mechanisms as targets for modulating PAR signalling in disease.
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Affiliation(s)
| | | | | | | | - Roland Kaufmann
- Department of General, Visceral and Vascular Surgery, Experimental Transplantation Surgery, Jena University Hospital, Drackendorfer Str, 1, D-07747, Jena, Germany.
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24
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Arachiche A, Mumaw MM, de la Fuente M, Nieman MT. Protease-activated receptor 1 (PAR1) and PAR4 heterodimers are required for PAR1-enhanced cleavage of PAR4 by α-thrombin. J Biol Chem 2013; 288:32553-32562. [PMID: 24097976 DOI: 10.1074/jbc.m113.472373] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombin is a potent platelet agonist that activates platelets and other cells of the cardiovascular system by cleaving its G-protein-coupled receptors, protease-activated receptor 1 (PAR1), PAR4, or both. We now show that cleaving PAR1 and PAR4 with α-thrombin induces heterodimer formation. PAR1-PAR4 heterodimers were not detected when unstimulated; however, when the cells were stimulated with 10 nm α-thrombin, we were able to detect a strong interaction between PAR1 and PAR4 by bioluminescence resonance energy transfer. In contrast, activating the receptors without cleavage using PAR1 and PAR4 agonist peptides (TFLLRN and AYPGKF, respectively) did not enhance heterodimer formation. Preventing PAR1 or PAR4 cleavage with point mutations or hirugen also prevented the induction of heterodimers. To further characterize the PAR1-PAR4 interactions, we mapped the heterodimer interface by introducing point mutations in transmembrane helix 4 of PAR1 or PAR4 that prevented heterodimer formation. Finally, we show that mutations in PAR1 or PAR4 at the heterodimer interface prevented PAR1-assisted cleavage of PAR4. These data demonstrate that PAR1 and PAR4 require allosteric changes induced via receptor cleavage by α-thrombin to mediate heterodimer formation, and we have determined the PAR1-PAR4 heterodimer interface. Our findings show that PAR1 and PAR4 have dynamic interactions on the cell surface that should be taken into account when developing and characterizing PAR antagonists.
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Affiliation(s)
- Amal Arachiche
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Michele M Mumaw
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - María de la Fuente
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Marvin T Nieman
- From the Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106.
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25
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Lin H, Liu AP, Smith TH, Trejo J. Cofactoring and dimerization of proteinase-activated receptors. Pharmacol Rev 2013; 65:1198-213. [PMID: 24064459 DOI: 10.1124/pr.111.004747] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Proteinase-activated receptors (PARs) are G protein-coupled receptors that transmit cellular responses to extracellular proteases and have important functions in vascular physiology, development, inflammation, and cancer progression. The established paradigm for PAR activation involves proteolytic cleavage of the extracellular N terminus, which reveals a new N terminus that functions as a tethered ligand by binding intramolecularly to the receptor to trigger transmembrane signaling. Most cells express more than one PAR, which can influence the mode of PAR activation and signaling. Clear examples include murine PAR3 cofactoring of PAR4 and transactivation of PAR2 by PAR1. Thrombin binds to and cleaves murine PAR3, which facilitates PAR4 cleavage and activation. This process is essential for thrombin signaling and platelet activation, since murine PAR3 cannot signal alone. Although PAR1 and PAR4 are both competent to signal, PAR1 is able to act as a cofactor for PAR4, facilitating more rapid cleavage and activation by thrombin. PAR1 can also facilitate PAR2 activation through a different mechanism. Cleavage of the PAR1 N terminus by thrombin generates a tethered ligand domain that can bind intermolecularly to PAR2 to activate signaling. Thus, PARs can regulate each other's activity by localizing thrombin when in complex with PAR3 and PAR4 or by cleaved PAR1, providing its tethered ligand domain for PAR2 activation. The ability of PARs to cofactor or transactivate other PARs would necessitate that the two receptors be in close proximity, likely in the form of a heterodimer. Here, we discuss the cofactoring and dimerization of PARs and the functional consequences on signaling.
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Affiliation(s)
- Huilan Lin
- University of California, San Diego, 9500 Gilman Drive, Biomedical Sciences Building, MC-0636, La Jolla, CA 92093.
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26
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Milligan G. The prevalence, maintenance, and relevance of G protein-coupled receptor oligomerization. Mol Pharmacol 2013; 84:158-69. [PMID: 23632086 DOI: 10.1124/mol.113.084780] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Over the past decade, ideas and experimental support for the hypothesis that G protein-coupled receptors may exist as dimeric or oligomeric complexes moved initially from heresy to orthodoxy, to the current situation in which the capacity of such receptors to interact is generally accepted but the prevalence, maintenance, and relevance of such interactions to both pharmacology and function remain unclear. A vast body of data obtained following transfection of cultured cells is still to be translated to native systems and, even where this has been attempted, results often remain controversial and contradictory. This review will consider approaches that are currently being applied and why these might be challenging to interpret, and will suggest means to overcome these limitations.
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Affiliation(s)
- Graeme Milligan
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom.
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27
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Arachiche A, de la Fuente M, Nieman MT. Calcium mobilization and protein kinase C activation downstream of protease activated receptor 4 (PAR4) is negatively regulated by PAR3 in mouse platelets. PLoS One 2013; 8:e55740. [PMID: 23405206 PMCID: PMC3566007 DOI: 10.1371/journal.pone.0055740] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/29/2012] [Indexed: 12/17/2022] Open
Abstract
Thrombin activates platelets through protease activated receptors (PARs). Mouse platelets express PAR3 and PAR4. PAR3 does not signal in platelets. However, PAR4 is a relatively poor thrombin substrate and requires PAR3 as a cofactor at low thrombin concentrations. In this study we show that PAR3 also regulates PAR4 signaling. In response to thrombin (30–100 nM) or PAR4 activating peptide (AYPGKF), platelets from PAR3−/− mice had increased Gq signaling compared to wild type mice as demonstrated by a 1.6-fold increase in the maximum intracellular calcium (Ca2+) mobilization, an increase in phosphorylation level of protein kinase C (PKC) substrates, and a 2-fold increase of Ca2+ release from intracellular stores. Moreover, platelets from heterozygous mice (PAR3+/−) had an intermediate increase in maximum Ca2+ mobilization. Treatment of PAR3−/− mice platelets with P2Y12 antagonist (2MeSAMP) did not affect Ca2+ mobilization from PAR4 in response to thrombin or AYPGKF. The activation of RhoA-GTP downstream G12/13 signaling in response to thrombin was not significantly different between wild type and PAR3−/− mice. Since PAR3 influenced PAR4 signaling independent of agonist, we examined the direct interaction between PAR3 and PAR4 with bioluminescence resonance energy transfer (BRET). PAR3 and PAR4 form constitutive homodimers and heterodimers. In summary, our results demonstrate that in addition to enhancing PAR4 activation at low thrombin concentrations, PAR3 negatively regulates PAR4-mediated maximum Ca2+ mobilization and PKC activation in mouse platelets by physical interaction.
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Affiliation(s)
- Amal Arachiche
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - María de la Fuente
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Marvin T. Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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28
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Kufareva I, Stephens B, Gilliland CT, Wu B, Fenalti G, Hamel D, Stevens RC, Abagyan R, Handel TM. A novel approach to quantify G-protein-coupled receptor dimerization equilibrium using bioluminescence resonance energy transfer. Methods Mol Biol 2013; 1013:93-127. [PMID: 23625495 PMCID: PMC4091634 DOI: 10.1007/978-1-62703-426-5_7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Along with other resonance energy transfer techniques, bioluminescence resonance energy transfer (BRET) has emerged as an important method for demonstrating protein-protein interactions in cells. In the field of G-protein-coupled receptors, including chemokine receptors, BRET has been widely used to investigate homo- and heterodimerization, a feature of their interactions that is emerging as integral to function and regulation. While demonstrating the existence of dimers for a given receptor proved to be fairly straightforward, quantitative comparisons of different receptors or mutants are nontrivial because of inevitable variations in the expression of receptor constructs. The uncontrollable parameters of the cellular expression machinery make amounts of transfected DNA extremely poor predictors for the expression levels of BRET donor and acceptor receptor constructs, even in relative terms. In this chapter, we show that properly accounting for receptor expression levels is critical for quantitative interpretation of BRET data. We also provide a comprehensive account of expected responses in all types of BRET experiments and propose a framework for uniform and accurate quantitative treatment of these responses. The framework allows analysis of both homodimer and heterodimer BRET data. The important caveats and obstacles for quantitative treatment are outlined, and the utility of the approach is illustrated by its application to the homodimerization of wild-type (WT) and mutant forms of the chemokine receptor CXCR4.
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Affiliation(s)
- Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Bryan Stephens
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - C. Taylor Gilliland
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Beili Wu
- The Scripps Research Institute, La Jolla, CA, USA
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Gus Fenalti
- The Scripps Research Institute, La Jolla, CA, USA
| | - Damon Hamel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | | | - Ruben Abagyan
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Tracy M. Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
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29
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Xiang B, Zhang G, Stefanini L, Bergmeier W, Gartner TK, Whiteheart SW, Li Z. The Src family kinases and protein kinase C synergize to mediate Gq-dependent platelet activation. J Biol Chem 2012; 287:41277-87. [PMID: 23066026 DOI: 10.1074/jbc.m112.393124] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Src family kinases (SFKs) play essential roles in collagen- and von Willebrand factor (VWF)-mediated platelet activation. However, the roles of SFKs in G protein-coupled receptor-mediated platelet activation and the molecular mechanisms whereby SFKs are activated by G protein-coupled receptor stimulation are not fully understood. Here we show that the thrombin receptor protease-activated receptor 4 agonist peptide AYPGKF elicited SFK phosphorylation in P2Y(12) deficient platelets but stimulated minimal SFK phosphorylation in platelets lacking G(q). We have previously shown that thrombin-induced SFK phosphorylation was inhibited by the calcium chelator 5,5'-dimethyl-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (dimethyl-BAPTA). The calcium ionophore A23187 induced SFK phosphorylation in both wild-type and G(q) deficient platelets. Together, these results indicate that SFK phosphorylation in response to thrombin receptor stimulation is downstream from G(q)/Ca(2+) signaling. Moreover, A23187-induced thromboxane A(2) synthesis, platelet aggregation, and secretion were inhibited by preincubation of platelets with a selective SFK inhibitor, PP2. AYPGKF-induced thromboxane A(2) production in wild-type and P2Y(12) deficient platelets was abolished by PP2, and AYPGKF-mediated P-selectin expression, integrin α(IIb)β(3) activation, and aggregation of P2Y(12) deficient platelets were partially inhibited by the PKC inhibitor Ro-31-8220, PP2, dimethyl-BAPTA, or LY294002, but were abolished by Ro-31-8220 plus PP2, dimethyl-BAPTA, or LY294002. These data indicate that Ca(2+)/SFKs/PI3K and PKC represent two alternative signaling pathways mediating G(q)-dependent platelet activation.
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Affiliation(s)
- Binggang Xiang
- Saha Cardiovascular Research Center, College of Medicine, University of Kentucky, Lexington, Kentucky 40536, USA
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