1
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Zhang Y, Zhao X, Shen B, Bai Y, Chang C, Stojanovic A, Wang C, Mack A, Deng G, Skidgel RA, Cheng N, Du X. Integrin β 3 directly inhibits the Gα 13-p115RhoGEF interaction to regulate G protein signaling and platelet exocytosis. Nat Commun 2023; 14:4966. [PMID: 37587112 PMCID: PMC10432399 DOI: 10.1038/s41467-023-40531-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 07/28/2023] [Indexed: 08/18/2023] Open
Abstract
The integrins and G protein-coupled receptors are both fundamental in cell biology. The cross talk between these two, however, is unclear. Here we show that β3 integrins negatively regulate G protein-coupled signaling by directly inhibiting the Gα13-p115RhoGEF interaction. Furthermore, whereas β3 deficiency or integrin antagonists inhibit integrin-dependent platelet aggregation and exocytosis (granule secretion), they enhance G protein-coupled RhoA activation and integrin-independent secretion. In contrast, a β3-derived Gα13-binding peptide or Gα13 knockout inhibits G protein-coupled RhoA activation and both integrin-independent and dependent platelet secretion without affecting primary platelet aggregation. In a mouse model of myocardial ischemia/reperfusion injury in vivo, the β3-derived Gα13-binding peptide inhibits platelet secretion of granule constituents, which exacerbates inflammation and ischemia/reperfusion injury. These data establish crucial integrin-G protein crosstalk, providing a rationale for therapeutic approaches that inhibit exocytosis in platelets and possibly other cells without adverse effects associated with loss of cell adhesion.
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Affiliation(s)
- Yaping Zhang
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Xiaojuan Zhao
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Bo Shen
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Yanyan Bai
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Claire Chang
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Aleksandra Stojanovic
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
- Dupage Medical Technology, Inc., Chicago, IL, 60612, USA
| | - Can Wang
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Andrew Mack
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Gary Deng
- Eli Lilly, Indianapolis, IN, 46285, USA
| | | | - Ni Cheng
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Xiaoping Du
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, USA.
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2
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von Willebrand factor links primary hemostasis to innate immunity. Nat Commun 2022; 13:6320. [PMID: 36329021 PMCID: PMC9633696 DOI: 10.1038/s41467-022-33796-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/30/2022] [Indexed: 11/06/2022] Open
Abstract
The plasma multimeric glycoprotein von Willebrand factor (VWF) plays a critical role in primary hemostasis by tethering platelets to exposed collagen at sites of vascular injury. Recent studies have identified additional biological roles for VWF, and in particular suggest that VWF may play an important role in regulating inflammatory responses. However, the molecular mechanisms through which VWF exerts its immuno-modulatory effects remain poorly understood. In this study, we report that VWF binding to macrophages triggers downstream MAP kinase signaling, NF-κB activation and production of pro-inflammatory cytokines and chemokines. In addition, VWF binding also drives macrophage M1 polarization and shifts macrophage metabolism towards glycolysis in a p38-dependent manner. Cumulatively, our findings define an important biological role for VWF in modulating macrophage function, and thereby establish a novel link between primary hemostasis and innate immunity.
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3
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Zhang Y, Ehrlich SM, Zhu C, Du X. Signaling mechanisms of the platelet glycoprotein Ib-IX complex. Platelets 2022; 33:823-832. [PMID: 35615944 PMCID: PMC9378482 DOI: 10.1080/09537104.2022.2071852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 04/03/2022] [Accepted: 04/23/2022] [Indexed: 12/14/2022]
Abstract
The glycoprotein Ib-IX (GPIb-IX) complex mediates initial platelet adhesion to von Willebrand factor (VWF) immobilized on subendothelial matrix and endothelial surfaces, and transmits VWF binding-induced signals to stimulate platelet activation. GPIb-IX also functions as part of a mechanosensor to convert mechanical force received via VWF binding into intracellular signals, thereby greatly enhancing platelet activation. Thrombin binding to GPIb-IX initiates GPIb-IX signaling cooperatively with protease-activated receptors to synergistically stimulate the platelet response to low-dose thrombin. GPIb-IX signaling may also occur following the binding of other GPIb-IX ligands such as leukocyte integrin αMβ2 and red cell-derived semaphorin 7A, contributing to thrombo-inflammation. GPIb-IX signaling requires the interaction between the cytoplasmic domains of GPIb-IX and 14-3-3 protein and is mediated through Src family kinases, the Rho family of small GTPases, phosphoinositide 3-kinase-Akt-cGMP-mitogen-activated protein kinase, and LIM kinase 1 signaling pathways, leading to calcium mobilization, integrin activation, and granule secretion. This review summarizes the current understanding of GPIb-IX signaling.
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Affiliation(s)
- Yaping Zhang
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago,Chicago, Illinois, USA
| | - Samuel M Ehrlich
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Cheng Zhu
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Xiaoping Du
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago,Chicago, Illinois, USA
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4
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Mandel J, Casari M, Stepanyan M, Martyanov A, Deppermann C. Beyond Hemostasis: Platelet Innate Immune Interactions and Thromboinflammation. Int J Mol Sci 2022; 23:ijms23073868. [PMID: 35409226 PMCID: PMC8998935 DOI: 10.3390/ijms23073868] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/29/2022] [Accepted: 03/29/2022] [Indexed: 02/07/2023] Open
Abstract
There is accumulating evidence that platelets play roles beyond their traditional functions in thrombosis and hemostasis, e.g., in inflammatory processes, infection and cancer, and that they interact, stimulate and regulate cells of the innate immune system such as neutrophils, monocytes and macrophages. In this review, we will focus on platelet activation in hemostatic and inflammatory processes, as well as platelet interactions with neutrophils and monocytes/macrophages. We take a closer look at the contributions of major platelet receptors GPIb, αIIbβ3, TLT-1, CLEC-2 and Toll-like receptors (TLRs) as well as secretions from platelet granules on platelet-neutrophil aggregate and neutrophil extracellular trap (NET) formation in atherosclerosis, transfusion-related acute lung injury (TRALI) and COVID-19. Further, we will address platelet-monocyte and macrophage interactions during cancer metastasis, infection, sepsis and platelet clearance.
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Affiliation(s)
- Jonathan Mandel
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (J.M.); (M.C.); (M.S.)
| | - Martina Casari
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (J.M.); (M.C.); (M.S.)
| | - Maria Stepanyan
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (J.M.); (M.C.); (M.S.)
- Center For Theoretical Problems of Physico-Chemical Pharmacology, 109029 Moscow, Russia;
- Physics Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology Immunology Ministry of Healthcare of Russian Federation, 117198 Moscow, Russia
| | - Alexey Martyanov
- Center For Theoretical Problems of Physico-Chemical Pharmacology, 109029 Moscow, Russia;
- Dmitriy Rogachev National Medical Research Center of Pediatric Hematology, Oncology Immunology Ministry of Healthcare of Russian Federation, 117198 Moscow, Russia
- N.M. Emanuel Institute of Biochemical Physics RAS (IBCP RAS), 119334 Moscow, Russia
| | - Carsten Deppermann
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (J.M.); (M.C.); (M.S.)
- Correspondence:
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5
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Bock F, Elias BC, Dong X, Parekh DV, Mernaugh G, Viquez OM, Hassan A, Amara VR, Liu J, Brown KL, Terker AS, Chiusa M, Gewin LS, Fogo AB, Brakebusch CH, Pozzi A, Zent R. Rac1 promotes kidney collecting duct integrity by limiting actomyosin activity. J Cell Biol 2021; 220:212704. [PMID: 34647970 PMCID: PMC8563289 DOI: 10.1083/jcb.202103080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/27/2021] [Accepted: 09/08/2021] [Indexed: 12/31/2022] Open
Abstract
A polarized collecting duct (CD), formed from the branching ureteric bud (UB), is a prerequisite for an intact kidney. The small Rho GTPase Rac1 is critical for actin cytoskeletal regulation. We investigated the role of Rac1 in the kidney collecting system by selectively deleting it in mice at the initiation of UB development. The mice exhibited only a mild developmental phenotype; however, with aging, the CD developed a disruption of epithelial integrity and function. Despite intact integrin signaling, Rac1-null CD cells had profound adhesion and polarity abnormalities that were independent of the major downstream Rac1 effector, Pak1. These cells did however have a defect in the WAVE2–Arp2/3 actin nucleation and polymerization apparatus, resulting in actomyosin hyperactivity. The epithelial defects were reversible with direct myosin II inhibition. Furthermore, Rac1 controlled lateral membrane height and overall epithelial morphology by maintaining lateral F-actin and restricting actomyosin. Thus, Rac1 promotes CD epithelial integrity and morphology by restricting actomyosin via Arp2/3-dependent cytoskeletal branching.
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Affiliation(s)
- Fabian Bock
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Bertha C Elias
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Xinyu Dong
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Diptiben V Parekh
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA
| | - Glenda Mernaugh
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Olga M Viquez
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Anjana Hassan
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Venkateswara Rao Amara
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Jiageng Liu
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Kyle L Brown
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Andrew S Terker
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Manuel Chiusa
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN
| | - Leslie S Gewin
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Agnes B Fogo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
| | - Cord H Brakebusch
- Biotech Research Center, University of Copenhagen, Copenhagen, Denmark
| | - Ambra Pozzi
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN.,Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Roy Zent
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
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6
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Dangelmaier C, Kunapuli SP. Protease-activated receptor 4 causes Akt phosphorylation independently of PI3 kinase pathways. Platelets 2021; 32:832-837. [PMID: 32811251 PMCID: PMC7889752 DOI: 10.1080/09537104.2020.1802415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 10/23/2022]
Abstract
PI-3 Kinase plays an important role in platelet activation mainly through regulation of RASA3. Akt phosphorylation is an indicator for the activity of PI3 kinase. The aim of this study is to characterize the pathways leading to Akt phosphorylation in platelets. We performed concentration response curves of LY294002, a pan-PI3 kinase inhibitor, on platelet aggregation and Akt phosphorylation, in washed human and mouse platelets. At concentrations as low as 3.12 µM, LY294002 abolished Akt phosphorylation induced by 2MeSADP and SFLLRN, but not by AYPGKF. It required much higher concentrations of LY294002 (12.5-25 µM) to abolish AYPGKF-induced Akt phosphorylation, both in wild type and P2Y12 null mouse platelets. We propose that 3.12 µM LY294002 is sufficient to inhibit PI3 kinase isoforms in platelets and higher concentrations might inhibit other pathways regulating Akt phosphorylation by AYPGKF. We conclude that Protease-activated receptor 4 (PAR4) might cause Akt phosphorylation through pathways distinctly different from those of Protease-activated receptor 1 (PAR1).
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Affiliation(s)
- Carol Dangelmaier
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Satya P Kunapuli
- Sol Sherry Thrombosis Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
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7
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Wu Y, Wu M, Yang J, Li Y, Peng W, Wu M, Yu C, Fang M. Silencing CircHIPK3 Sponges miR-93-5p to Inhibit the Activation of Rac1/PI3K/AKT Pathway and Improves Myocardial Infarction-Induced Cardiac Dysfunction. Front Cardiovasc Med 2021; 8:645378. [PMID: 33996942 PMCID: PMC8119651 DOI: 10.3389/fcvm.2021.645378] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/12/2021] [Indexed: 01/24/2023] Open
Abstract
The ceRNA network involving circular RNAs (circRNAs) is essential in the cardiovascular system. We investigated the underlying ceRNA network involving circHIPK3 in myocardial infarction (MI). After an MI model was established, cardiac function was verified, and myocardial tissue damage in mice with MI was evaluated. A hypoxia model of cardiomyocytes was used to simulate MI in vivo, and the expression of and targeting relationships among circHIPK3, miR-93-5p, and Rac1 were verified. The apoptosis of cardiomyocyte was identified. Gain- and loss-of-functions were performed to verify the ceRNA mechanism. The MI-modeled mice showed cardiac dysfunction and enlarged infarct size. CircHIPK3 was highly expressed in mouse and cell models of MI. Silencing circHIPK3 reduced infarct size, myocardial collagen deposition, and myocardial apoptosis rate and improved cardiac function. CircHIPK3 sponged miR-93-5p, and miR-93-5p targeted Rac1. Overexpression of miR-93-5p inhibited MI-induced cardiomyocyte injury and eliminated the harmful effect of circHIPK3. CircHIPK3 acted as ceRNA to absorb miR-93-5p, thus promoting the activation of the Rac1/PI3K/AKT pathway. We highlighted that silencing circHIPK3 can upregulate miR-93-5p and then inhibit the activation of Rac1/PI3K/Akt pathway, which can improve MI-induced cardiac dysfunction.
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Affiliation(s)
- Yijin Wu
- Department of Intensive Care Unit of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China
| | - Min Wu
- Department of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China
| | - Jue Yang
- Department of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China
| | - Ying Li
- Department of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China
| | - Wenying Peng
- Department of Intensive Care Unit of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China
| | - Meifen Wu
- Department of Intensive Care Unit of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China
| | - Changjiang Yu
- Department of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China,Changjiang Yu
| | - Miaoxian Fang
- Department of Intensive Care Unit of Cardiac Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China,*Correspondence: Miaoxian Fang
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8
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GPR56/ADGRG1 is a platelet collagen-responsive GPCR and hemostatic sensor of shear force. Proc Natl Acad Sci U S A 2020; 117:28275-28286. [PMID: 33097663 PMCID: PMC7668045 DOI: 10.1073/pnas.2008921117] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We identified the known collagen receptor GPR56/ADGRG1 on platelets. GPR56 is an adhesion G protein-coupled receptor that becomes activated following forced dissociation of its N-terminal fragment and C-terminal fragment or seven-transmembrane spanning domain (7TM). Fragment dissociation reveals the cryptic stalk of the 7TM, which acts as a tethered peptide agonist, and for GPR56, this activates platelet G13 signaling. GPR56 pharmacological probes activated platelets to undergo shape change and aggregation, which are critical for the formation of hemostatic plugs. Gpr56−/− mice exhibit prolonged bleeding, defective platelet plug formation in vessel injury assays, and delayed thrombotic vessel occlusion. Shear-force dependency of platelet adhesion to immobilized collagen was found to be GPR56 dependent. Circulating platelets roll along exposed collagen at vessel injury sites and respond with filipodia protrusion, shape change, and surface area expansion to facilitate platelet adhesion and plug formation. Various glycoproteins were considered to be both collagen responders and mediators of platelet adhesion, yet the signaling kinetics emanating from these receptors do not fully account for the rapid platelet cytoskeletal changes that occur in blood flow. We found the free N-terminal fragment of the adhesion G protein-coupled receptor (GPCR) GPR56 in human plasma and report that GPR56 is the platelet receptor that transduces signals from collagen and blood flow-induced shear force to activate G protein 13 signaling for platelet shape change. Gpr56−/− mice have prolonged bleeding, defective platelet plug formation, and delayed thrombotic occlusion. Human and mouse blood perfusion studies demonstrated GPR56 and shear-force dependence of platelet adhesion to immobilized collagen. Our work places GPR56 as an initial collagen responder and shear-force transducer that is essential for platelet shape change during hemostasis.
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9
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El Haouari M. Platelet Oxidative Stress and its Relationship with Cardiovascular Diseases in Type 2 Diabetes Mellitus Patients. Curr Med Chem 2019; 26:4145-4165. [PMID: 28982316 DOI: 10.2174/0929867324666171005114456] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 06/07/2017] [Accepted: 06/07/2017] [Indexed: 01/01/2023]
Abstract
Enhanced platelet activation and thrombosis are linked to various cardiovascular diseases (CVD). Among other mechanisms, oxidative stress seems to play a pivotal role in platelet hyperactivity. Indeed, upon stimulation by physiological agonists, human platelets generate and release several types of reactive oxygen species (ROS) such as O2 -, H2O2 or OH-, further amplifying the platelet activation response via various signalling pathways, including, formation of isoprostanes, Ca2+ mobilization and NO inactivation. Furthermore, excessive platelet ROS generation, incorporation of free radicals from environment and/or depletion of antioxidants induce pro-oxidant, pro-inflammatory and platelet hyperaggregability effects, leading to the incidence of cardiovascular events. Here, we review the current knowledge regarding the effect of oxidative stress on platelet signaling pathways and its implication in CVD such as type 2 diabetes mellitus. We also summarize the role of natural antioxidants included in vegetables, fruits and medicinal herbs in reducing platelet function via an oxidative stress-mediated mechanism.
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Affiliation(s)
- Mohammed El Haouari
- Centre Regional des Metiers de l'Education et de la Formation de Taza (CRMEF - Taza), B.P: 1178 - Taza Gare, Morocco
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10
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Abstract
The vasculature is a dynamic environment in which blood platelets constantly survey the endothelium for sites of vessel damage. The formation of a mechanically coherent hemostatic plug to prevent blood loss relies on a coordinated series of ligand-receptor interactions governing the recruitment, activation, and aggregation of platelets. The physical biology of each step is distinct in that the recruitment of platelets depends on the mechanosensing of the platelet receptor glycoprotein Ib for the adhesive protein von Willebrand factor, whereas platelet activation and aggregation are responsive to the mechanical forces sensed at adhesive junctions between platelets and at the platelet-matrix interface. Herein we take a biophysical perspective to discuss the current understanding of platelet mechanotransduction as well as the measurement techniques used to quantify the physical biology of platelets in the context of thrombus formation under flow.
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Affiliation(s)
- Caroline E Hansen
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, Georgia 30332, USA; .,Wallace H. Coulter Department of Biomedical Engineering and Institute for Electronics and Nanotechnology, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA
| | - Yongzhi Qiu
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, Georgia 30332, USA; .,Wallace H. Coulter Department of Biomedical Engineering and Institute for Electronics and Nanotechnology, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA
| | - Owen J T McCarty
- Department of Cell, Developmental, and Cancer Biology, Oregon Health & Science University, Portland, Oregon 97239, USA.,Division of Hematology and Medical Oncology and Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Wilbur A Lam
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, Georgia 30332, USA; .,Wallace H. Coulter Department of Biomedical Engineering and Institute for Electronics and Nanotechnology, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA
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11
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Møller LLV, Klip A, Sylow L. Rho GTPases-Emerging Regulators of Glucose Homeostasis and Metabolic Health. Cells 2019; 8:E434. [PMID: 31075957 PMCID: PMC6562660 DOI: 10.3390/cells8050434] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 12/11/2022] Open
Abstract
Rho guanosine triphosphatases (GTPases) are key regulators in a number of cellular functions, including actin cytoskeleton remodeling and vesicle traffic. Traditionally, Rho GTPases are studied because of their function in cell migration and cancer, while their roles in metabolism are less documented. However, emerging evidence implicates Rho GTPases as regulators of processes of crucial importance for maintaining metabolic homeostasis. Thus, the time is now ripe for reviewing Rho GTPases in the context of metabolic health. Rho GTPase-mediated key processes include the release of insulin from pancreatic β cells, glucose uptake into skeletal muscle and adipose tissue, and muscle mass regulation. Through the current review, we cast light on the important roles of Rho GTPases in skeletal muscle, adipose tissue, and the pancreas and discuss the proposed mechanisms by which Rho GTPases act to regulate glucose metabolism in health and disease. We also describe challenges and goals for future research.
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Affiliation(s)
- Lisbeth Liliendal Valbjørn Møller
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100 Copenhagen Oe, Denmark.
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.
| | - Lykke Sylow
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100 Copenhagen Oe, Denmark.
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12
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Abstract
Platelets play important roles in blood clotting, hemostasis and wound repair, while more and more research show that platelets also have significant contributions in the process of inflammation. Rheumatoid arthritis is a chronic systemic inflammatory autoimmune disease. Platelet microparticles, which are membrane vesicles shed by activated platelets, are reported to amplify inflammation in Rheumatoid arthritis. Here we show that either platelet-specific deletion of Rac1 (Rac1-/-) or Rac1-specific inhibitor NSC23766 dramatically inhibit platelet-derived microparticles formation. As we all know, collagen-induced arthritis (CIA) mouse model is the most common autoimmune model of rheumatoid arthritis. Interestingly, NSC23766 alleviated the process of collagen-induced arthritis of DBA mice in vivo, including the reduced hind paw thickness and ankle stiffness, the reduction of arthritic scores and incidence of arthritis. Our work also found that NSC23766-treated CIA mouse spleen is less swollen and contains less enlarged white pulp than PBS control. The histological analysis shows that NSC23766-treated but not solvent control improve the cartilage erosion symptom in the joint of CIA mouse. Interestingly, platelet microparticles in the peripheral blood of NSC23766-treated CIA mice were decreased significantly compared with PBS-treated CIA mice. In conclusion, our work demonstrated that Rac1 inhibition alleviates collagen-induced arthritis through the decrease of platelet microparticles' release. In short, Rac1 aggravate the rheumatoid arthritis deterioration through the regulation of platelet microparticles formation.
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Affiliation(s)
- Xue Chen
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai, China
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13
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14-3-3 proteins in platelet biology and glycoprotein Ib-IX signaling. Blood 2018; 131:2436-2448. [PMID: 29622550 DOI: 10.1182/blood-2017-09-742650] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 03/25/2018] [Indexed: 12/16/2022] Open
Abstract
Members of the 14-3-3 family of proteins function as adapters/modulators that recognize phosphoserine/phosphothreonine-based binding motifs in many intracellular proteins and play fundamental roles in signal transduction pathways of eukaryotic cells. In platelets, 14-3-3 plays a wide range of regulatory roles in phosphorylation-dependent signaling pathways, including G-protein signaling, cAMP signaling, agonist-induced phosphatidylserine exposure, and regulation of mitochondrial function. In particular, 14-3-3 interacts with several phosphoserine-dependent binding sites in the major platelet adhesion receptor, the glycoprotein Ib-IX complex (GPIb-IX), regulating its interaction with von Willebrand factor (VWF) and mediating VWF/GPIb-IX-dependent mechanosignal transduction, leading to platelet activation. The interaction of 14-3-3 with GPIb-IX also plays a critical role in enabling the platelet response to low concentrations of thrombin through cooperative signaling mediated by protease-activated receptors and GPIb-IX. The various functions of 14-3-3 in platelets suggest that it is a possible target for the treatment of thrombosis and inflammation.
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14
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Fc-independent immune thrombocytopenia via mechanomolecular signaling in platelets. Blood 2017; 131:787-796. [PMID: 29203584 DOI: 10.1182/blood-2017-05-784975] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 11/27/2017] [Indexed: 01/13/2023] Open
Abstract
Immune thrombocytopenia (ITP) is a prevalent autoimmune disease characterized by autoantibody-induced platelet clearance. Some ITP patients are refractory to standard immunosuppressive treatments such as intravenous immunoglobulin (IVIg). These patients often have autoantibodies that target the ligand-binding domain (LBD) of glycoprotein Ibα (GPIbα), a major subunit of the platelet mechanoreceptor complex GPIb-IX. However, the molecular mechanism of this Fc-independent platelet clearance is not clear. Here, we report that many anti-LBD monoclonal antibodies such as 6B4, but not AK2, activated GPIb-IX in a shear-dependent manner and induced IVIg-resistant platelet clearance in mice. Single-molecule optical tweezer measurements of antibodies pulling on full-length GPIb-IX demonstrated that the unbinding force needed to dissociate 6B4 from the LBD far exceeds the force required to unfold the juxtamembrane mechanosensory domain (MSD) in GPIbα, unlike the AK2-LBD unbinding force. Binding of 6B4, not AK2, induced shear-dependent unfolding of the MSD on the platelet, as evidenced by increased exposure of a linear sequence therein. Imaging flow cytometry and aggregometry measurements of platelets and LBD-coated platelet-mimetic beads revealed that 6B4 can sustain crosslinking of platelets under shear, whereas 6B4 Fab and AK2 cannot. These results suggest a novel mechanism by which anti-LBD antibodies can exert a pulling force on GPIb-IX via platelet crosslinking, activating GPIb-IX by unfolding its MSD and inducing Fc-independent platelet clearance.
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15
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Estevez B, Du X. New Concepts and Mechanisms of Platelet Activation Signaling. Physiology (Bethesda) 2017; 32:162-177. [PMID: 28228483 DOI: 10.1152/physiol.00020.2016] [Citation(s) in RCA: 190] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Upon blood vessel injury, platelets are exposed to adhesive proteins in the vascular wall and soluble agonists, which initiate platelet activation, leading to formation of hemostatic thrombi. Pathological activation of platelets can induce occlusive thrombosis, resulting in ischemic events such as heart attack and stroke, which are leading causes of death globally. Platelet activation requires intracellular signal transduction initiated by platelet receptors for adhesion proteins and soluble agonists. Whereas many platelet activation signaling pathways have been established for many years, significant recent progress reveals much more complex and sophisticated signaling and amplification networks. With the discovery of new receptor signaling pathways and regulatory networks, some of the long-standing concepts of platelet signaling have been challenged. This review provides an overview of the new developments and concepts in platelet activation signaling.
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Affiliation(s)
- Brian Estevez
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Xiaoping Du
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois
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16
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Thaper D, Vahid S, Nip KM, Moskalev I, Shan X, Frees S, Roberts ME, Ketola K, Harder KW, Gregory-Evans C, Bishop JL, Zoubeidi A. Targeting Lyn regulates Snail family shuttling and inhibits metastasis. Oncogene 2017; 36:3964-3975. [PMID: 28288135 DOI: 10.1038/onc.2017.5] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 11/27/2016] [Accepted: 12/27/2016] [Indexed: 02/06/2023]
Abstract
The acquisition of an invasive phenotype by epithelial cells occurs through a loss of cellular adhesion and polarity, heralding a multistep process that leads to metastatic dissemination. Since its characterization in 1995, epithelial-mesenchymal transition (EMT) has been closely linked to the metastatic process. As a defining aspect of EMT, loss of cell adhesion through downregulation of E-cadherin is carried out by several transcriptional repressors; key among them the SNAI family of transcription factors. Here we identify for the first time that Lyn kinase functions as a key modulator of SNAI family protein localization and stability through control of the Vav-Rac1-PAK1 (Vav-Rac1-p21-activated kinase) pathway. Accordingly, targeting Lyn in vitro reduces EMT and in vivo reduces metastasis of primary tumors. We also demonstrate the clinical relevance of targeting Lyn as a key player controlling EMT; patient samples across many cancers revealed a strong negative correlation between Lyn and E-cadherin, and high Lyn expression in metastatic tumors as well as metastasis-prone primary tumors. This work reveals a novel pancancer mechanism of Lyn-dependent control of EMT and further underscores the role of this kinase in tumor progression.
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Affiliation(s)
- D Thaper
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada.,Faculty of Medicine, Department of Urologic Science, University of British Columbia, Vancouver, BC, Canada
| | - S Vahid
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada.,Faculty of Medicine, Department of Urologic Science, University of British Columbia, Vancouver, BC, Canada
| | - K M Nip
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada.,Faculty of Medicine, Department of Urologic Science, University of British Columbia, Vancouver, BC, Canada
| | - I Moskalev
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - X Shan
- Faculty of Medicine, Department Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - S Frees
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - M E Roberts
- Faculty of Science, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - K Ketola
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - K W Harder
- Faculty of Science, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - C Gregory-Evans
- Faculty of Medicine, Department Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - J L Bishop
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - A Zoubeidi
- Department of Urology, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada.,Faculty of Medicine, Department of Urologic Science, University of British Columbia, Vancouver, BC, Canada
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17
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Unsworth AJ, Flora GD, Sasikumar P, Bye AP, Sage T, Kriek N, Crescente M, Gibbins JM. RXR Ligands Negatively Regulate Thrombosis and Hemostasis. Arterioscler Thromb Vasc Biol 2017; 37:812-822. [PMID: 28254816 PMCID: PMC5405776 DOI: 10.1161/atvbaha.117.309207] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 02/13/2017] [Indexed: 12/17/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— Platelets have been found to express intracellular nuclear receptors including the retinoid X receptors (RXRα and RXRβ). Treatment of platelets with ligands of RXR has been shown to inhibit platelet responses to ADP and thromboxane A2; however, the effects on responses to other platelet agonists and the underlying mechanism have not been fully characterized. Approach and Results— The effect of 9-cis-retinoic acid, docosahexaenoic acid and methoprene acid on collagen receptor (glycoprotein VI [GPVI]) agonists and thrombin-stimulated platelet function; including aggregation, granule secretion, integrin activation, calcium mobilization, integrin αIIbβ3 outside-in signaling and thrombus formation in vitro and in vivo were determined. Treatment of platelets with RXR ligands resulted in attenuation of platelet functional responses after stimulation by GPVI agonists or thrombin and inhibition of integrin αIIbβ3 outside-in signaling. Treatment with 9-cis-retinoic acid caused inhibition of thrombus formation in vitro and an impairment of thrombosis and hemostasis in vivo. Both RXR ligands stimulated protein kinase A activation, measured by VASP S157 phosphorylation, that was found to be dependent on both cAMP and nuclear factor κ-light-chain-enhancer of activated B cell activity. Conclusions— This study identifies a widespread, negative regulatory role for RXR in the regulation of platelet functional responses and thrombus formation and describes novel events that lead to the upregulation of protein kinase A, a known negative regulator of many aspects of platelet function. This mechanism may offer a possible explanation for the cardioprotective effects described in vivo after treatment with RXR ligands.
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Affiliation(s)
- Amanda J Unsworth
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom
| | - Gagan D Flora
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom
| | - Parvathy Sasikumar
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom
| | - Alexander P Bye
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom
| | - Tanya Sage
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom
| | - Neline Kriek
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom
| | - Marilena Crescente
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom
| | - Jonathan M Gibbins
- From the Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, United Kingdom.
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18
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Signaling-mediated cooperativity between glycoprotein Ib-IX and protease-activated receptors in thrombin-induced platelet activation. Blood 2015; 127:626-36. [PMID: 26585954 DOI: 10.1182/blood-2015-04-638387] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 11/12/2015] [Indexed: 11/20/2022] Open
Abstract
Thrombin-induced cellular response in platelets not only requires protease-activated receptors (PARs), but also involves another thrombin receptor, the glycoprotein Ib-IX complex (GPIb-IX). It remains controversial how thrombin binding to GPIb-IX stimulates platelet responses. It was proposed that GPIb-IX serves as a dock that facilitates thrombin cleavage of protease-activated receptors, but there are also reports suggesting that thrombin binding to GPIb-IX induces platelet activation independent of PARs. Here we show that GPIb is neither a passive thrombin dock nor a PAR-independent signaling receptor. We demonstrate a novel signaling-mediated cooperativity between PARs and GPIb-IX. Low-dose thrombin-induced PAR-dependent cell responses require the cooperativity of GPIb-IX signaling, and conversely, thrombin-induced GPIb-IX signaling requires cooperativity of PARs. This mutually dependent cooperativity requires a GPIb-IX-specific 14-3-3-Rac1-LIMK1 signaling pathway, and activation of this pathway also requires PAR signaling. The cooperativity between GPIb-IX signaling and PAR signaling thus drives platelet activation at low concentrations of thrombin, which are important for in vivo thrombosis.
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19
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Nagy Z, Wynne K, von Kriegsheim A, Gambaryan S, Smolenski A. Cyclic Nucleotide-dependent Protein Kinases Target ARHGAP17 and ARHGEF6 Complexes in Platelets. J Biol Chem 2015; 290:29974-83. [PMID: 26507661 DOI: 10.1074/jbc.m115.678003] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Indexed: 01/01/2023] Open
Abstract
Endothelial cells release prostacyclin (PGI2) and nitric oxide (NO) to inhibit platelet functions. PGI2 and NO effects are mediated by cyclic nucleotides, cAMP- and cGMP-dependent protein kinases (PKA, PKG), and largely unknown PKA and PKG substrate proteins. The small G-protein Rac1 plays a key role in platelets and was suggested to be a target of cyclic nucleotide signaling. We confirm that PKA and PKG activation reduces Rac1-GTP levels. Screening for potential mediators of this effect resulted in the identification of the Rac1-specific GTPase-activating protein ARHGAP17 and the guanine nucleotide exchange factor ARHGEF6 as new PKA and PKG substrates in platelets. We mapped the PKA/PKG phosphorylation sites to serine 702 on ARHGAP17 using Phos-tag gels and to serine 684 on ARHGEF6. We show that ARHGAP17 binds to the actin-regulating CIP4 protein in platelets and that Ser-702 phosphorylation interferes with this interaction. Reduced CIP4 binding results in enhanced inhibition of cell migration by ARHGAP17. Furthermore, we show that ARHGEF6 is constitutively linked to GIT1, a GAP of Arf family small G proteins, and that ARHGEF6 phosphorylation enables binding of the 14-3-3 adaptor protein to the ARHGEF6/GIT1 complex. PKA and PKG induced rearrangement of ARHGAP17- and ARHGEF6-associated protein complexes might contribute to Rac1 regulation and platelet inhibition.
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Affiliation(s)
- Zoltan Nagy
- From the UCD Conway Institute and the School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Kieran Wynne
- Mass Spectrometry Resource, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | | | - Stepan Gambaryan
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez Prospect, St. Petersburg, 194223 Russia
| | - Albert Smolenski
- From the UCD Conway Institute and the School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland,
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20
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Namba T, Funahashi Y, Nakamuta S, Xu C, Takano T, Kaibuchi K. Extracellular and Intracellular Signaling for Neuronal Polarity. Physiol Rev 2015; 95:995-1024. [PMID: 26133936 DOI: 10.1152/physrev.00025.2014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Neurons are one of the highly polarized cells in the body. One of the fundamental issues in neuroscience is how neurons establish their polarity; therefore, this issue fascinates many scientists. Cultured neurons are useful tools for analyzing the mechanisms of neuronal polarization, and indeed, most of the molecules important in their polarization were identified using culture systems. However, we now know that the process of neuronal polarization in vivo differs in some respects from that in cultured neurons. One of the major differences is their surrounding microenvironment; neurons in vivo can be influenced by extrinsic factors from the microenvironment. Therefore, a major question remains: How are neurons polarized in vivo? Here, we begin by reviewing the process of neuronal polarization in culture conditions and in vivo. We also survey the molecular mechanisms underlying neuronal polarization. Finally, we introduce the theoretical basis of neuronal polarization and the possible involvement of neuronal polarity in disease and traumatic brain injury.
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Affiliation(s)
- Takashi Namba
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuhiro Funahashi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinichi Nakamuta
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Chundi Xu
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tetsuya Takano
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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21
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Aegeline from Aegle marmelos stimulates glucose transport via Akt and Rac1 signaling, and contributes to a cytoskeletal rearrangement through PI3K/Rac1. Eur J Pharmacol 2015; 762:419-29. [PMID: 26102565 DOI: 10.1016/j.ejphar.2015.05.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 05/10/2015] [Accepted: 05/14/2015] [Indexed: 11/21/2022]
Abstract
Aegeline is an alkaloidal-amide, isolated from the leaves of Aegle marmelos and have shown antihyperglycemic as well as antidyslipidemic activities in the validated animal models of type 2 diabetes mellitus. Here we delineate, aegeline enhanced GLUT4 translocation mediated 2-deoxy-glucose uptake in both time and concentration-dependent manner. 2-deoxy-glucose uptake was completely stymied by the transport inhibitors (wortmannin and genistein) in C2C12 myotubes. Pharmacological inhibition of Akt (also known as protein kinase B) and Ras-related C3 botulinum toxin substrate 1 (Rac1) suggest that both Akt and Rac1 operate aegeline-stimulated glucose transport via distinct parallel pathways. Moreover, aegeline activates p21 protein-activated kinase 1 (PAK1) and cofilin (an actin polymerization regulator). Rac1 inhibitor (Rac1 inhib II) and PAK1 inhibitor (IPA-3) completely blocked aegeline-induced phosphorylation of cofilin and p21 protein-activated kinase 1 (PAK1). In summary, these findings suggest that aegeline stimulates the glucose transport through Akt and Rac1 dependent distinct parallel pathways and have cytoskeletal roles via stimulation of the PI3-kinase-Rac1-PAK1-cofilin pathway in the skeletal muscle cells. Therefore, multiple targets of aegeline in the improvement of insulin sensitivity of the skeletal muscle cells may be suggested.
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22
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Dütting S, Heidenreich J, Cherpokova D, Amin E, Zhang SC, Ahmadian MR, Brakebusch C, Nieswandt B. Critical off-target effects of the widely used Rac1 inhibitors NSC23766 and EHT1864 in mouse platelets. J Thromb Haemost 2015; 13:827-38. [PMID: 25628054 DOI: 10.1111/jth.12861] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 01/10/2015] [Indexed: 12/25/2022]
Abstract
BACKGROUND Platelet aggregation at sites of vascular injury is essential for normal hemostasis, but may also cause pathologic vessel occlusion. Rho GTPases are molecular switches that regulate essential cellular processes, and they have pivotal functions in the cardiovascular system. Rac1 is an important regulator of platelet cytoskeletal reorganization, and contributes to platelet activation. Rac1 inhibitors are thought to be beneficial in a wide range of therapeutic settings, and have therefore been tested in vivo for a variety of disorders. Two small-molecule inhibitors, NSC23766 and EHT1864, have been characterized in different cell types, demonstrating high specificity for Rac1 and Rac, respectively. OBJECTIVES To analyze the specificity of NSC23766 and EHT1864. METHODS Platelet function was assessed in mouse wild-type and Rac1-deficient platelets by the use of flow cytometric analysis of cellular activation and aggregometry. Platelet spreading was analyzed with differential interference contrast microscopy, and activation of effector molecules was analyzed with biochemical approaches. RESULTS NSC23766 and EHT1864 showed strong and distinct Rac1-independent effects at 100 μm in platelet function tests. Both inhibitors induced Rac1-specific inhibition of platelet spreading, but also markedly impaired agonist-induced activation of Rac1(-/-) platelets. Furthermore, glycoprotein Ib-mediated signaling was dramatically inhibited by NSC23766 in both wild-type and Rac1-deficient platelets. Importantly, these inhibitors directly affected the activation of the Rac1 effectors p21-activated kinase (PAK)1 and PAK2. CONCLUSIONS Our results reveal critical off-target effects of NSC23766 and EHT1864 at 100 μm in mammalian cells, raising questions about their utility as specific Rac1/Rac inhibitors in biochemical studies at these concentrations and possibly as therapeutic agents.
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Affiliation(s)
- S Dütting
- Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
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23
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Elvers M. RhoGAPs and Rho GTPases in platelets. Hamostaseologie 2015; 36:168-77. [PMID: 25639730 DOI: 10.5482/hamo-14-09-0046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 01/13/2015] [Indexed: 01/03/2023] Open
Abstract
Platelet cytoskeletal reorganization is essential for platelet adhesion and thrombus formation in hemostasis and thrombosis. The Rho GTPases RhoA, Rac1 and Cdc42 are the main players in cytoskeletal dynamics of platelets responsible for the formation of filopodia and lamellipodia to strongly increase the platelet surface upon activation. They are involved in platelet activation and aggregate formation including platelet secretion, integrin activation and arterial thrombus formation. The activity of Rho GTPases is tightly controlled by different proteins such as GTPase-activating proteins (GAPs). GAPs stimulate GTP hydrolysis to terminate Rho signaling. The role and impact of GAPs in platelets is not well-defined and many of the RhoGAPs identified are not known to be present in platelets or to have any function in platelets. The recently identified RhoGAPs Oligophrenin1 (OPHN1) and Nadrin regulate the activity of RhoA, Rac1 and Cdc42 and subsequent platelet cytoskeletal reorganization, platelet activation and thrombus formation. In the last years, the analysis of genetically modified mice helped to gain the understanding of Rho GTPases and their regulators in cytoskeletal rearrangements and other Rho mediated cellular processes in platelets.
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Affiliation(s)
- Margitta Elvers
- Margitta Elvers, Ph.D., Department of Clinical and Experimental Hemostasis, Hemotherapy and Transfusion Medicine, Heinrich-Heine-University Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany, Tel. +49/(0)211/81-08851, Fax -17498., E-mail:
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24
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Bryckaert M, Rosa JP, Denis CV, Lenting PJ. Of von Willebrand factor and platelets. Cell Mol Life Sci 2014; 72:307-26. [PMID: 25297919 PMCID: PMC4284388 DOI: 10.1007/s00018-014-1743-8] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/05/2014] [Accepted: 09/25/2014] [Indexed: 11/26/2022]
Abstract
Hemostasis and pathological thrombus formation are dynamic processes that require multiple adhesive receptor-ligand interactions, with blood platelets at the heart of such events. Many studies have contributed to shed light on the importance of von Willebrand factor (VWF) interaction with its platelet receptors, glycoprotein (GP) Ib-IX-V and αIIbβ3 integrin, in promoting primary platelet adhesion and aggregation following vessel injury. This review will recapitulate our current knowledge on the subject from the rheological aspect to the spatio-temporal development of thrombus formation. We will also discuss the signaling events generated by VWF/GPIb-IX-V interaction, leading to platelet activation. Additionally, we will review the growing body of evidence gathered from the recent development of pathological mouse models suggesting that VWF binding to GPIb-IX-V is a promising target in arterial and venous pathological thrombosis. Finally, the pathological aspects of VWF and its impact on platelets will be addressed.
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Affiliation(s)
- Marijke Bryckaert
- INSERM U770, Hôpital Bicêtre, 80 rue du Général Leclerc, 94276, Le Kremlin Bicêtre Cedex, France,
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25
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Agonist-induced platelet procoagulant activity requires shear and a Rac1-dependent signaling mechanism. Blood 2014; 124:1957-67. [PMID: 25079357 DOI: 10.1182/blood-2014-03-560821] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Activated platelets facilitate blood coagulation by exposing phosphatidylserine (PS) and releasing microvesicles (MVs). However, the potent physiological agonists thrombin and collagen poorly induce PS exposure when a single agonist is used. To obtain a greater procoagulant response, thrombin is commonly used in combination with glycoprotein VI agonists. However, even under these conditions, only a percentage of platelets express procoagulant activity. To date, it remains unclear why platelets poorly expose PS even when stimulated with multiple agonists and what the signaling pathways are of soluble agonist-induced platelet procoagulant activity. Here we show that physiological levels of shear present in blood significantly enhance agonist-induced platelet PS exposure and MV release, enabling low doses of a single agonist to induce full-scale platelet procoagulant activity. PS exposed on the platelet surface was immediately released as MVs, revealing a tight coupling between the 2 processes under shear. Using platelet-specific Rac1(-/-) mice, we discovered that Rac1 plays a common role in mediating the low-dose agonist-induced procoagulant response independent of platelet aggregation, secretion, and the apoptosis pathway. Platelet-specific Rac1 function was not only important for coagulation in vitro but also for fibrin accumulation in vivo following laser-induced arteriolar injury.
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26
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Sylow L, Kleinert M, Pehmøller C, Prats C, Chiu TT, Klip A, Richter EA, Jensen TE. Akt and Rac1 signaling are jointly required for insulin-stimulated glucose uptake in skeletal muscle and downregulated in insulin resistance. Cell Signal 2014; 26:323-31. [DOI: 10.1016/j.cellsig.2013.11.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 11/01/2013] [Indexed: 11/16/2022]
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27
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A directional switch of integrin signalling and a new anti-thrombotic strategy. Nature 2013; 503:131-5. [PMID: 24162846 PMCID: PMC3823815 DOI: 10.1038/nature12613] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 08/28/2013] [Indexed: 01/07/2023]
Abstract
Integrins are critical in thrombosis and hemostasis1. Antagonists of the platelet integrin αIIbβ3 are potent anti-thrombotic drugs, but also have the life-threatening adverse effect of bleeding2,3. It is thus desirable to develop new antagonists that do not cause bleeding. Integrins transmit signals bidirectionally4,5. Inside-out signaling activates integrins via a talin-dependent mechanism6,7. Integrin ligation mediates thrombus formation and outside-in signaling8,9, which requires Gα13 and greatly expands thrombi. Here we show that Gα13 and talin bind to mutually exclusive, but distinct sites within the integrin β3 cytoplasmic domain in opposing waves. The first talin binding wave mediates inside-out signaling and also “ligand-induced integrin activation”, but is not required for outside-in signaling. Integrin ligation induces transient talin dissociation and Gα13 binding to an ExE motif, which selectively mediates outside-in signaling and platelet spreading. The second talin binding wave is associated with clot retraction. An ExE motif-based inhibitor of Gα13-integrin interaction selectively abolishes outside-in signaling without affecting integrin ligation, and suppresses occlusive arterial thrombosis without affecting bleeding time. Thus, we have discovered a novel mechanism for the directional switch of integrin signaling and, based on this mechanism, we designed a potent new anti-thrombotic that does not cause bleeding.
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28
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Abstract
von Willebrand factor (vWF) secretion by endothelial cells (ECs) is essential for hemostasis and thrombosis; however, the molecular mechanisms are poorly understood. Interestingly, we observed increased bleeding in EC-Gα13(-/-);Gα12(-/-) mice that could be normalized by infusion of human vWF. Blood from Gα12(-/-) mice exhibited significantly reduced vWF levels but normal vWF multimers and impaired laser-induced thrombus formation, indicating that Gα12 plays a prominent role in EC vWF secretion required for hemostasis and thrombosis. In isolated buffer-perfused mouse lungs, basal vWF levels were significantly reduced in Gα12(-/-), whereas thrombin-induced vWF secretion was defective in both EC-Gαq(-/-);Gα11(-/-) and Gα12(-/-) mice. Using siRNA in cultured human umbilical vein ECs and human pulmonary artery ECs, depletion of Gα12 and soluble N-ethylmaleimide-sensitive-fusion factor attachment protein α (α-SNAP), but not Gα13, inhibited both basal and thrombin-induced vWF secretion, whereas overexpression of activated Gα12 promoted vWF secretion. In Gαq, p115 RhoGEF, and RhoA-depleted human umbilical vein ECs, thrombin-induced vWF secretion was reduced by 40%, whereas basal secretion was unchanged. Finally, in vitro binding assays revealed that Gα12 N-terminal residues 10-15 mediated the binding of Gα12 to α-SNAP, and an engineered α-SNAP binding-domain minigene peptide blocked basal and evoked vWF secretion. Discovery of obligatory and complementary roles of Gα12 and Gαq/11 in basal vs evoked EC vWF secretion may provide promising new therapeutic strategies for treatment of thrombotic disease.
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29
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LIM kinase-1 selectively promotes glycoprotein Ib-IX-mediated TXA2 synthesis, platelet activation, and thrombosis. Blood 2013; 121:4586-94. [PMID: 23620575 DOI: 10.1182/blood-2012-12-470765] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Current antithrombotic drugs have an adverse effect on bleeding, highlighting the need for new molecular targets for developing antithrombotic drugs that minimally affect hemostasis. Here we show that LIMK1(-/-) mice have defective arterial thrombosis in vivo but do not differ from wild-type mice with respect to bleeding time. LIMK1(-/-) mice show a selective defect in platelet activation induced through the von Willebrand Factor (VWF) receptor, the glycoprotein Ib-IX-V complex (GPIb-IX), but not by GPIb-IX-independent platelet agonists. In fact, LIMK1(-/-) platelets show an enhanced reaction to certain GPIb-IX-independent agonists. The defect of LIMK1(-/-) platelets in GPIb-IX-mediated platelet activation is attributed to a selective inhibition in VWF/GPIb-IX-induced phosphorylation of cytosolic phospholipase A2 (cPLA2) and consequent thromboxane A2 (TXA2) production. Supplementing a TXA2 analog, U46619, corrected the defect of LIMK1(-/-) platelets in VWF-induced stable platelet adhesion. Although LIMK1(-/-) platelets also showed reduced actin polymerization after GPIb-IX-mediated platelet aggregation, actin polymerization inhibitors did not reduce TXA2 generation, but rather accelerated platelet aggregation, suggesting that the role of LIMK1 in GPIb-mediated platelet activation is independent of actin polymerization. Thus, LIMK1 plays a novel role in selectively mediating GPIb-IX-dependent TXA2 synthesis and thrombosis and represents a potential target for developing antithrombotic drugs with minimal bleeding side effect.
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Abstract
The Rho family of GTP binding proteins, also commonly referred to as the Rho GTPases, are master regulators of the platelet cytoskeleton and platelet function. These low-molecular-weight or 'small' GTPases act as signaling switches in the spatial and temporal transduction, and amplification of signals from platelet cell surface receptors to the intracellular signaling pathways that drive platelet function. The Rho GTPase family members RhoA, Cdc42 and Rac1 have emerged as key regulators in the dynamics of the actin cytoskeleton in platelets and play key roles in platelet aggregation, secretion, spreading and thrombus formation. Rho GTPase regulators, including GEFs and GAPs and downstream effectors, such as the WASPs, formins and PAKs, may also regulate platelet activation and function. In this review, we provide an overview of Rho GTPase signaling in platelet physiology. Previous studies of Rho GTPases and platelets have had a shared history, as platelets have served as an ideal, non-transformed cellular model to characterize Rho function. Likewise, recent studies of the cell biology of Rho GTPase family members have helped to build an understanding of the molecular regulation of platelet function and will continue to do so through the further characterization of Rho GTPases as well as Rho GAPs, GEFs, RhoGDIs and Rho effectors in actin reorganization and other Rho-driven cellular processes.
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Affiliation(s)
- J E Aslan
- Department of Biomedical Engineering and Cell & Developmental Biology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA.
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