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Cook JB, Piatt R, Marson L. [Lys 5,MeLeu 9,Nle 10]-NKA (4-10) induces neurokinin 2 receptor mediated urination and defecation and neurokinin 1 receptor mediated flushing in rats: measured using the rapid detection voiding assay. J Basic Clin Physiol Pharmacol 2023; 34:227-233. [PMID: 36377965 PMCID: PMC10015449 DOI: 10.1515/jbcpp-2022-0119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 10/19/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Neurokinin 2 receptor (NK2R) agonists may be useful for treating bladder and bowel dysfunction via direct contraction of detrusor and gastrointestinal smooth muscle. The NK2R agonist [Lys5, MeLeu9, Nle10]-NKA(4-10) (LMN-NKA) induces urination and defecation, but also produces the potential side effect of dermal flushing in rats. Although LMN-NKA is a NK2R agonist, it also has affinity for neurokinin 1 receptors (NK1R). Therefore, the goal of this study was to determine the neurokinin receptor (NKR) subtypes responsible for LMN-NKA-induced urination, defecation, and flushing by blocking either NK2Rs or NK1Rs before LMN-NKA administration. METHODS To accomplish this goal, we developed a simple high-throughput 'rapid detection voiding assay' to detect rapid-onset drug-induced urination and defecation in rats. In LMN-NKA dose-response experiments, LMN-NKA (10-100 μg/kg, subcutaneous) was injected and urination, defecation, and flushing were monitored for 30 min. For NKR antagonist experiments, vehicle, the NK2R antagonist GR159897, or the NK1R antagonist CP-99,994 were injected before an acclimation period. Following acclimation, saline or 100 μg/kg LMN-NKA were injected, and behavior was observed for 30 min. RESULTS LMN-NKA produced dose-related increases in urination, defecation, and flushing. Blocking NK2Rs reduced urination and blocked defecation, without affecting flushing. Blocking NK1Rs did not change LMN-NKA-induced urination or defecation but reduced LMN-NKA-induced flushing. CONCLUSIONS Using the rapid detection voiding assay we show that LMN-NKA-induced urination and defecation are mediated by NK2Rs, while flushing is mediated by NK1Rs. Therefore, drugs that are more selective for NK2 vs. NK1Rs should produce rapid-onset urination and defecation without producing the potential side effect of flushing.
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Affiliation(s)
- Jason B Cook
- Dignify Therapeutics LLC, Research Triangle Park, NC, USA
| | - Raymond Piatt
- Dignify Therapeutics LLC, Research Triangle Park, NC, USA
| | - Lesley Marson
- Dignify Therapeutics LLC, Research Triangle Park, NC, USA
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Marson L, Piatt R, Cook JB, Thor KB. Neurokinin 2 receptor-mediated bladder and colorectal responses in aged spinal cord injured rats. Spinal Cord 2021; 59:1013-1017. [PMID: 34404911 DOI: 10.1038/s41393-021-00684-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Animal proof of principle study. OBJECTIVES Bladder and bowel dysfunction are common after spinal cord injury (SCI) and in the elderly. Neurokinin 2 receptor agonists are known to produce on-demand urination and defecation in adult SCI rats. This study compared the ability of a neurokinin 2 receptor (NK2R) agonist to produce bladder and colorectal contractions in both young adult and aged SCI rats. SETTING Dignify Therapeutics and Integrated Laboratory Systems, Durham, NC USA. METHODS Bladder and colorectal pressure and voiding efficiency were measured in response to the NK2R agonist, [Lys5,Me,Leu9,Nle10]-NKA(4-10) (LMN-NKA), in anesthetized animals. The potency and efficacy of LMN-NKA was examined in young adult and aged SCI (T3 or T9 transected) rats, with young adult and aged spinal intact rats included as controls. RESULTS LMN-NKA (3-300 μg/kg i.v.) produced dose-dependent increases in bladder and colorectal pressure in all anesthetized rats. No differences in the bladder or colorectal pressure responses or voiding efficiency were observed with age or after SCI. The level of SCI did not change the pharmacodynamic responses to the agonist. CONCLUSIONS An NK2R agonist produced similar responses in young adult and aged SCI rats, suggesting this class of agonists could be used as a potential therapy to induce on-demand urination and defecation in aged populations, with or without SCI.
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Lee RH, Piatt R, Dhenge A, Lozano ML, Palma-Barqueros V, Rivera J, Bergmeier W. Impaired hemostatic activity of healthy transfused platelets in inherited and acquired platelet disorders: Mechanisms and implications. Sci Transl Med 2019; 11:eaay0203. [PMID: 31826978 PMCID: PMC10824274 DOI: 10.1126/scitranslmed.aay0203] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/11/2019] [Indexed: 12/21/2022]
Abstract
Platelet transfusions can fail to prevent bleeding in patients with inherited platelet function disorders (IPDs), such as Glanzmann's thrombasthenia (GT; integrin αIIbβ3 dysfunction), Bernard-Soulier syndrome [BSS; glycoprotein (GP) Ib/V/IX dysfunction], and the more recently identified nonsyndromic RASGRP2 variants. Here, we used IPD mouse models and real-time imaging of hemostatic plug formation to investigate whether dysfunctional platelets impair the hemostatic function of healthy donor [wild-type (WT)] platelets. In Rasgrp2-/- mice or mice with platelet-specific deficiency in the integrin adaptor protein TALIN1 ("GT-like"), WT platelet transfusion was ineffective unless the ratio between mutant and WT platelets was ~2:1. In contrast, thrombocytopenic mice or mice lacking the extracellular domain of GPIbα ("BSS-like") required very few transfused WT platelets to normalize hemostasis. Both Rasgrp2-/- and GT-like, but not BSS-like, platelets effectively localized to the injury site. Mechanistic studies identified at least two mechanisms of interference by dysfunctional platelets in IPDs: (i) delayed adhesion of WT donor platelets due to reduced access to GPIbα ligands exposed at sites of vascular injury and (ii) impaired consolidation of the hemostatic plug. We also investigated the hemostatic activity of transfused platelets in the setting of dual antiplatelet therapy (DAPT), an acquired platelet function disorder (APD). "DAPT" platelets did not prolong the time to initial hemostasis, but plugs were unstable and frequent rebleeding was observed. Thus, we propose that the endogenous platelet count and the ratio of transfused versus endogenous platelets should be considered when treating select IPD and APD patients with platelet transfusions.
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Affiliation(s)
- Robert H Lee
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
- UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Raymond Piatt
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Ankita Dhenge
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
- UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - María L Lozano
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia 30003, Spain
| | - Verónica Palma-Barqueros
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia 30003, Spain
| | - José Rivera
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia 30003, Spain
| | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
- UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
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Akbar H, Duan X, Piatt R, Saleem S, Davis AK, Tandon NN, Bergmeier W, Zheng Y. Small molecule targeting the Rac1-NOX2 interaction prevents collagen-related peptide and thrombin-induced reactive oxygen species generation and platelet activation. J Thromb Haemost 2018; 16:2083-2096. [PMID: 30007118 PMCID: PMC6472274 DOI: 10.1111/jth.14240] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Indexed: 12/29/2022]
Abstract
Essentials Reactive oxygen species (ROS) generation by NOX2 plays a critical role in platelet activation. Rac1 regulation of NOX2 is important for ROS generation. Small molecule inhibitor of the Rac1-p67phox interaction prevents platelet activation. Pharmacologic targeting of Rac1-NOX2 axis can be a viable approach for antithrombotic therapy. SUMMARY Background Platelets from patients with X-linked chronic granulomatous disease or mice deficient in nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) oxidase isoform NOX2 exhibit diminished reactive oxygen species (ROS) generation and platelet activation. Binding of Rac1 GTPase to p67phox plays a critical role in NOX2 activation by facilitating the assembly of the NOX2 enzyme complex. Objective We tested the hypothesis that Phox-I, a rationally designed small molecule inhibitor of Rac-p67phox interaction, may serve as an antithrombosis agent by suppressing ROS production and platelet activation. Results Collagen-related peptide (CRP) induced ROS generation in a time-dependent manner. Platelets from Rac1-/- mice or human platelets treated with NSC23766, a specific Rac inhibitor, produced significantly less ROS in response to CRP. Treatment of platelets with Phox-I inhibited diverse CRP-induced responses, including: (i) ROS generation; (ii) release of P-selectin; (iii) secretion of ATP; (iv) platelet aggregation; and (v) phosphorylation of Akt. Similarly, incubation of platelets with Phox-I inhibited thrombin-induced: (i) secretion of ATP; (ii) platelet aggregation; (iii) rise in cytosolic calcium; and (iv) phosphorylation of Akt. In mouse models, intraperitoneal administration of Phox-I inhibited: (i) collagen-induced platelet aggregation without affecting the tail bleeding time and (ii) in vivo platelet adhesion/accumulation at the laser injury sites on the saphenous vein without affecting the time for complete cessation of blood loss. Conclusions Small molecule targeting of the Rac1-p67phox interaction may present an antithrombosis regimen by preventing GPVI- and non-GPVI-mediated NOX2 activation, ROS generation and platelet function without affecting the bleeding time.
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Affiliation(s)
- H Akbar
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - X Duan
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA
| | - R Piatt
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - S Saleem
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - A K Davis
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA
| | | | - W Bergmeier
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | - Y Zheng
- Division of Experimental Hematology and Cancer Biology, Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA
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Battram AM, Durrant TN, Agbani EO, Heesom KJ, Paul DS, Piatt R, Poole AW, Cullen PJ, Bergmeier W, Moore SF, Hers I. The Phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) Binder Rasa3 Regulates Phosphoinositide 3-kinase (PI3K)-dependent Integrin αIIbβ3 Outside-in Signaling. J Biol Chem 2017; 292:1691-1704. [PMID: 27903653 PMCID: PMC5290945 DOI: 10.1074/jbc.m116.746867] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/14/2016] [Indexed: 11/16/2022] Open
Abstract
The class I PI3K family of lipid kinases plays an important role in integrin αIIbβ3 function, thereby supporting thrombus growth and consolidation. Here, we identify Ras/Rap1GAP Rasa3 (GAP1IP4BP) as a major phosphatidylinositol 3,4,5-trisphosphate-binding protein in human platelets and a key regulator of integrin αIIbβ3 outside-in signaling. We demonstrate that cytosolic Rasa3 translocates to the plasma membrane in a PI3K-dependent manner upon activation of human platelets. Expression of wild-type Rasa3 in integrin αIIbβ3-expressing CHO cells blocked Rap1 activity and integrin αIIbβ3-mediated spreading on fibrinogen. In contrast, Rap1GAP-deficient (P489V) and Ras/Rap1GAP-deficient (R371Q) Rasa3 had no effect. We furthermore show that two Rasa3 mutants (H794L and G125V), which are expressed in different mouse models of thrombocytopenia, lack both Ras and Rap1GAP activity and do not affect integrin αIIbβ3-mediated spreading of CHO cells on fibrinogen. Platelets from thrombocytopenic mice expressing GAP-deficient Rasa3 (H794L) show increased spreading on fibrinogen, which in contrast to wild-type platelets is insensitive to PI3K inhibitors. Together, these results support an important role for Rasa3 in PI3K-dependent integrin αIIbβ3-mediated outside-in signaling and cell spreading.
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Affiliation(s)
- Anthony M Battram
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Tom N Durrant
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Ejaife O Agbani
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Kate J Heesom
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - David S Paul
- the McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Raymond Piatt
- the McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Alastair W Poole
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Peter J Cullen
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Wolfgang Bergmeier
- the McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Samantha F Moore
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Ingeborg Hers
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom.
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Lee RH, Piatt R, Conley PB, Bergmeier W. Effects of ibrutinib treatment on murine platelet function during inflammation and in primary hemostasis. Haematologica 2016; 102:e89-e92. [PMID: 27979925 DOI: 10.3324/haematol.2016.155978] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Robert H Lee
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Raymond Piatt
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Wolfgang Bergmeier
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA .,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, NC, USA
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Piatt R, Paul DS, Lee RH, McKenzie SE, Parise LV, Cowley DO, Cooley BC, Bergmeier W. Mice Expressing Low Levels of CalDAG-GEFI Exhibit Markedly Impaired Platelet Activation With Minor Impact on Hemostasis. Arterioscler Thromb Vasc Biol 2016; 36:1838-46. [PMID: 27417588 DOI: 10.1161/atvbaha.116.307874] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/05/2016] [Indexed: 12/27/2022]
Abstract
OBJECTIVE The tight regulation of platelet adhesiveness, mediated by the αIIbβ3 integrin, is critical for hemostasis and prevention of thrombosis. We recently demonstrated that integrin affinity in platelets is controlled by the guanine nucleotide exchange factor, CalDAG-GEFI (CD-GEFI), and its target, RAP1. In this study, we investigated whether low-level expression of CD-GEFI leads to protection from thrombosis without pathological bleeding in mice. APPROACH AND RESULTS Cdg1(low) mice were generated by knockin of human CD-GEFI cDNA into the mouse Cdg1 locus. CD-GEFI expression in platelets from Cdg1(low) mice was reduced by ≈90% when compared with controls. Activation of RAP1 and αIIbβ3 was abolished at low agonist concentrations and partially inhibited at high agonist concentrations in Cdg1(low) platelets. Consistently, the aggregation response of Cdg1(low) platelets was weaker than that of wild-type platelets, but more efficient than that observed in Cdg1(-/-) platelets. Importantly, Cdg1(low) mice were strongly protected from arterial and immune complex-mediated thrombosis, with only minimal impact on primary hemostasis. CONCLUSIONS Together, our studies suggest the partial inhibition of CD-GEFI function as a powerful new approach to safely prevent thrombotic complications.
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Affiliation(s)
- Raymond Piatt
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill
| | - David S Paul
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill
| | - Robert H Lee
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill
| | - Steven E McKenzie
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill
| | - Leslie V Parise
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill
| | - Dale O Cowley
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill
| | - Brian C Cooley
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill
| | - Wolfgang Bergmeier
- From the McAllister Heart Institute, University of North Carolina, Chapel Hill (R.P., D.S.P., R.H.L., W.B.); Cardeza Foundation for Hematological Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.E.M.); Department of Biochemistry and Biophysics (L.V.P., W.B.), Animal Models Core (D.O.C.), and Rodent Advanced Surgical Core (B.C.C.), University of North Carolina at Chapel Hill.
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Boulaftali Y, Owens AP, Beale A, Piatt R, Casari C, Lee RH, Conley PB, Paul DS, Mackman N, Bergmeier W. CalDAG-GEFI Deficiency Reduces Atherosclerotic Lesion Development in Mice. Arterioscler Thromb Vasc Biol 2016; 36:792-9. [PMID: 26988592 DOI: 10.1161/atvbaha.115.306347] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/28/2016] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Platelets are important for the development and progression of atherosclerotic lesions. However, relatively little is known about the contribution of platelet signaling to this pathological process. Our recent work identified 2 independent, yet synergistic, signaling pathways that lead to the activation of the small GTPase Rap1; one mediated by the guanine nucleotide exchange factor, CalDAG-GEFI (CDGI), the other by P2Y12, a platelet receptor for adenosine diphosphate and the target of antiplatelet drugs. In this study, we evaluated lesion formation in atherosclerosis-prone low-density lipoprotein receptor deficient (Ldlr(-/-)) mice lacking CDGI or P2Y12 in hematopoietic cells. APPROACH AND RESULTS Lethally irradiated Ldlr(-/-) mice were reconstituted with bone marrow from wild-type (WT), Caldaggef1(-/-) (cdgI(-/-)), p2y12(-/-), or cdgI(-/-)p2y12(-/-) (double knockout [DKO]) mice and fed a high-fat diet for 12 weeks. Ldlr(-/-) chimeras deficient for CDGI or P2Y12 developed significantly smaller atherosclerotic lesions in the aortic sinus and in aortas when compared with the Ldlr(-/-)/WT controls. We also observed a significant reduction in platelet-leukocyte aggregates in blood from hypercholesterolemic Ldlr(-/-)/cdgI(-/-) and Ldlr(-/-)/p2y12(-/-) chimeras. Consistently, fewer macrophages and neutrophils were detected in the aortic sinus of Ldlr(-/-)/cdgI(-/-) and Ldlr(-/-)/ p2y12(-/-) chimeras. Compared with controls, the plaque collagen content was significantly higher in Ldlr(-/-) chimeras lacking CDGI. Interestingly, no statistically significant additive effects were seen in Ldlr(-/-)/DKO chimeras when compared with chimeras lacking only CDGI. CONCLUSIONS Our findings suggest that CDGI is critical for atherosclerotic plaque development in hypercholesterolemic Ldlr(-/-) mice because of its contribution to platelet-leukocyte aggregate formation and leukocyte recruitment to the lesion area.
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Affiliation(s)
- Yacine Boulaftali
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - A Phillip Owens
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - Ashley Beale
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - Raymond Piatt
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - Caterina Casari
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - Robert H Lee
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - Pamela B Conley
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - David S Paul
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - Nigel Mackman
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.)
| | - Wolfgang Bergmeier
- From the McAllister Heart Institute and Department of Medicine (Y.B., A.P.O., A.B., R.P., C.C., R.H.L., D.S.P., N.M., W.B.), Department of Biochemistry and Biophysics (W.B.), University of North Carolina at Chapel Hill; and Portola Pharmaceuticals, South San Francisco, CA (P.B.C.).
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Getz TM, Piatt R, Petrich BG, Monroe D, Mackman N, Bergmeier W. Novel mouse hemostasis model for real-time determination of bleeding time and hemostatic plug composition. J Thromb Haemost 2015; 13:417-25. [PMID: 25442192 PMCID: PMC4414118 DOI: 10.1111/jth.12802] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 11/20/2014] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Hemostasis is a rapid response by the body to stop bleeding at sites of vessel injury. Both platelets and fibrin are important for the formation of a hemostatic plug. Mice have been used to uncover the molecular mechanisms that regulate the activation of platelets and coagulation under physiologic conditions. However, measurements of hemostasis in mice are quite variable, and current methods do not quantify platelet adhesion or fibrin formation at the site of injury. METHODS We describe a novel hemostasis model that uses intravital fluorescence microscopy to quantify platelet adhesion, fibrin formation and time to hemostatic plug formation in real time. Repeated vessel injuries of ~ 50-100 μm in diameter were induced with laser ablation technology in the saphenous vein of mice. RESULTS Hemostasis in this model was strongly impaired in mice deficient in glycoprotein Ibα or talin-1, which are important regulators of platelet adhesiveness. In contrast, the time to hemostatic plug formation was only minimally affected in mice deficient in the extrinsic tissue factor (TF(low)) or the intrinsic factor IX coagulation pathways, even though platelet adhesion was significantly reduced. A partial reduction in platelet adhesiveness obtained with clopidogrel led to instability within the hemostatic plug, especially when combined with impaired coagulation in TF(low) mice. CONCLUSIONS In summary, we present a novel, highly sensitive method to quantify hemostatic plug formation in mice. On the basis of its sensitivity to platelet adhesion defects and its real-time imaging capability, we propose this model as an ideal tool with which to study the efficacy and safety of antiplatelet agents.
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Affiliation(s)
- T M Getz
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
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Stefanini L, Paul DS, Robledo RF, Chan ER, Getz TM, Campbell RA, Kechele DO, Casari C, Piatt R, Caron KM, Mackman N, Weyrich AS, Parrott MC, Boulaftali Y, Adams MD, Peters LL, Bergmeier W. RASA3 is a critical inhibitor of RAP1-dependent platelet activation. J Clin Invest 2015; 125:1419-32. [PMID: 25705885 DOI: 10.1172/jci77993] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/13/2015] [Indexed: 01/15/2023] Open
Abstract
The small GTPase RAP1 is critical for platelet activation and thrombus formation. RAP1 activity in platelets is controlled by the GEF CalDAG-GEFI and an unknown regulator that operates downstream of the adenosine diphosphate (ADP) receptor, P2Y12, a target of antithrombotic therapy. Here, we provide evidence that the GAP, RASA3, inhibits platelet activation and provides a link between P2Y12 and activation of the RAP1 signaling pathway. In mice, reduced expression of RASA3 led to premature platelet activation and markedly reduced the life span of circulating platelets. The increased platelet turnover and the resulting thrombocytopenia were reversed by concomitant deletion of the gene encoding CalDAG-GEFI. Rasa3 mutant platelets were hyperresponsive to agonist stimulation, both in vitro and in vivo. Moreover, activation of Rasa3 mutant platelets occurred independently of ADP feedback signaling and was insensitive to inhibitors of P2Y12 or PI3 kinase. Together, our results indicate that RASA3 ensures that circulating platelets remain quiescent by restraining CalDAG-GEFI/RAP1 signaling and suggest that P2Y12 signaling is required to inhibit RASA3 and enable sustained RAP1-dependent platelet activation and thrombus formation at sites of vascular injury. These findings provide insight into the antithrombotic effect of P2Y12 inhibitors and may lead to improved diagnosis and treatment of platelet-related disorders.
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Boulaftali Y, Paul DS, Piatt R, Feng D, Cooley BC, Most P, Bergmeier W. Abstract 21: The Calcium-Binding Protein S100A1 Negatively Regulates Collagen-Dependent Platelet Activation and Thrombosis in Mice. Arterioscler Thromb Vasc Biol 2014. [DOI: 10.1161/atvb.34.suppl_1.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction:
S100A1 is a member of the S100 family of calcium-binding proteins. S100A1 controls Ca2+ dynamics in cardiomyocytes and plays an important role in heart failure. S100A1 is also strongly expressed in mouse platelets, but its role in platelet biology has not been investigated.
Goal:
To determine the role of S100A1 in platelet activation and thrombosis.
Methods and Results:
Platelet activation in response to threshold levels of convulxin, a specific agonist for the collagen receptor GPVI, showed significantly increased activation of αIIbβ3 integrin and α-granule release in S100A1-deficient (SKO) platelets compared with wild-type (WT) platelets. Consistently, SKO platelets also showed a more robust aggregation response to convulxin and collagen. In contrast, SKO platelets responded normally to stimulation with PAR4 receptor-activating peptide or ADP. Adhesion of SKO platelets to collagen under flow conditions was not significantly different to that of WT platelets. However, we observed a ~3-fold increase in phosphatidylserine (PS)-positive SKO platelets bound to the collagen surface (p<0.001, n=9 mice/group), suggesting that S100A1 also regulates the procoagulant response in platelets. Consistent with this hypothesis, we observed increased coated platelet formation and more sustained calcium transients in SKO platelets compared to controls. The increased reactivity of SKO platelets to GPVI agonists is explained by a ~1.5-fold increase in GPVI receptors expressed on the surface of these cells (p<0.001, n=20 mice/group). A similar increase in GPVI expression was also found in bone marrow-derived megakaryocytes. When subjected to the FeCl3 carotid artery thrombosis model, the time to vessel occlusion was significantly shorter in SKO mice compared to WT controls (4.55 ± 0.27 min vs 7.00 ± 0.62 min, respectively; p<0.01; n=8 mice/group). Furthermore, by using a collagen-rich adventitial surface inserted intralumenally in the carotid artery, we observed that thrombus formation in SKO mice is significantly more stable compared to WT mice (p=0.01, n=7 WT, n=8 SKO)
Conclusions:
We here identify S100A1 as a negative regulator of GPVI expression and collagen-dependent platelet activation and thrombosis in mice.
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Affiliation(s)
- Yacine Boulaftali
- Biophysics and biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - David S Paul
- Biophysics and biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Raymond Piatt
- Biophysics and biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Dengmin Feng
- Biology Dept, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Brian C Cooley
- Dept of Pathology and Laboratory Medicine, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Patrick Most
- Biophysics and biochemistry, Heidelberg Univ Hosp, Heidelberg Univ, Heidelberg, Germany
| | - Wolfgang Bergmeier
- Biophysics and biochemistry. McAllister Heart Institute, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
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Holly S, Chang J, Li W, Niessen S, Phillips R, Piatt R, Black J, Smith M, Boulaftali Y, Weyrich A, Bergmeier W, Cravatt B, Parise L. Discovery of a lipid deacetylase (AADACL1) as a novel regulator of platelet activation (999.4). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.999.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Stephen Holly
- Biochemistry and Biophysics University of North Carolina at CHAPEL HILLChapel HillNCUnited States
| | - Jae Chang
- Chemical Physiology The Scripps Institute LA JollaCAUnited States
| | - Weiwei Li
- Chemical Physiology The Scripps Institute LA JollaCAUnited States
| | - Sherry Niessen
- Chemical Physiology The Scripps Institute LA JollaCAUnited States
| | - Ryan Phillips
- Pharmacology University of North Carolina at CHAPEL HILLChapel HillNCUnited States
| | - Raymond Piatt
- Biochemistry and Biophysics University of North Carolina at CHAPEL HILLChapel HillNCUnited States
| | - Justin Black
- Biochemistry and Biophysics University of North Carolina at CHAPEL HILLChapel HillNCUnited States
| | - Matthew Smith
- Internal Medicine University of UtahSalt Lake CityUTUnited States
| | - Yacine Boulaftali
- Biochemistry and Biophysics University of North Carolina at CHAPEL HILLChapel HillNCUnited States
| | - Andrew Weyrich
- Internal Medicine University of UtahSalt Lake CityUTUnited States
| | - Wolfgang Bergmeier
- Biochemistry and Biophysics University of North Carolina at CHAPEL HILLChapel HillNCUnited States
| | - Benjamin Cravatt
- Chemical Physiology The Scripps Institute LA JollaCAUnited States
| | - Leslie Parise
- Biochemistry and Biophysics University of North Carolina at CHAPEL HILLChapel HillNCUnited States
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Holly SP, Chang JW, Li W, Niessen S, Phillips RM, Piatt R, Black JL, Smith MC, Boulaftali Y, Weyrich AS, Bergmeier W, Cravatt BF, Parise LV. Chemoproteomic discovery of AADACL1 as a regulator of human platelet activation. ACTA ACUST UNITED AC 2013; 20:1125-34. [PMID: 23993462 DOI: 10.1016/j.chembiol.2013.07.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/19/2013] [Accepted: 07/23/2013] [Indexed: 12/27/2022]
Abstract
A comprehensive knowledge of the platelet proteome is necessary for understanding thrombosis and for envisioning antiplatelet therapies. To discover other biochemical pathways in human platelets, we screened platelets with a carbamate library designed to interrogate the serine hydrolase subproteome and used competitive activity-based protein profiling to map the targets of active carbamates. We identified an inhibitor that targets arylacetamide deacetylase-like 1 (AADACL1), a lipid deacetylase originally identified in invasive cancers. Using this compound, along with highly selective second-generation inhibitors of AADACL1, metabolomics, and RNA interference, we show that AADACL1 regulates platelet aggregation, thrombus growth, RAP1 and PKC activation, lipid metabolism, and fibrinogen binding to platelets and megakaryocytes. These data provide evidence that AADACL1 regulates platelet and megakaryocyte activation and highlight the value of this chemoproteomic strategy for target discovery in platelets.
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Affiliation(s)
- Stephen P Holly
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Boulaftali Y, Owens A, Beale A, Piatt R, Andre P, Conley PB, Mackman N, Bergmeier W. Abstract 130: Platelet Rap1 Signaling, Mediated by CalDAG-GEFI and P2Y12, Contributes to Atherosclerotic Lesion Development in Mice. Arterioscler Thromb Vasc Biol 2013. [DOI: 10.1161/atvb.33.suppl_1.a130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Objective
The development and progression of atherosclerotic lesions is mediated by various blood cell types, including platelets and neutrophils. We recently identified CalDAG-GEFI (CDGI) as a critical component of integrin-mediated adhesion of platelets and neutrophils at sites of vascular injury. In platelets, signaling by CDGI mediates the early activation of Rap1, while receptor for ADP, P2Y12, the target of the clinically used drug Plavix, is required for sustained Rap1 activation and thrombus stability. In this study, we evaluated lesion formation in atherosclerosis-prone low-density lipoprotein receptor deficient (Ldlr-/-) mice lacking CDGI and/or P2Y12 in hematopoietic cells.
Methods and Results
Ldlr-/- mice were irradiated and reconstituted with bone-marrow from wild-type (WT), CalDAG-GEFI-/- (CdgI), P2y12-/-, or CdgI-/- P2y12-/- (DKO) mice. Reconstituted mice were fed a fat and cholesterol enriched diet (21% fat, 0.2% cholesterol) for 12 weeks, ad libitum. Atherosclerotic lesions in the aortic sinus of Ldlr-/-;CdgI-/- chimeras were 42% smaller than those in Ldlr-/-;WT controls (0.18 ± 0.02 mm2 vs 0.31 ± 0.05 mm2, respectively; n = 13 each group, p < 0.001). Lesions in Ldlr-/-;P2y12-/- chimeras were also significantly smaller compared to controls (0.22 ± 0.10 mm2; n = 13, p < 0.05). Lesions in Ldlr-/-;DKO were reduced by 48% compared to WT controls (0.16 ± 0.02 mm2; n = 13, p < 0.001 ), but they were not statistically different from Ldlr-/-;CdgI-/- chimeras. Platelet adhesion and activation on collagen under flow was markedly impaired in Ldlr-/-;CdgI-/- and Ldlr-/-;DKO blood, but only partially impaired in Ldlr-/-;P2y12-/- blood. Importantly, firm neutrophil adhesion to collagen-bound platelets was significantly reduced in Ldlr-/-;CdgI-/- and Ldlr-/-;DKO blood, but not in Ldlr-/-;P2y12-/- blood. Total cholesterol and triglyceride levels were similar among groups.
Conclusion
Our findings reveal a critical role for CDGI and P2Y12, and Rap1-dependent platelet activation, in promoting atherosclerotic lesion development in hypercholesterolemic mice. Further studies are required to determine if the observed protection in Ldlr-/-;CdgI-/- chimeras is due to impaired neutrophil function.
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Affiliation(s)
- Yacine Boulaftali
- Biophysics and biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - A.Phillip Owens
- Mc Allister Heart Institute, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Ashley Beale
- Biophysics and biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Raymond Piatt
- Biophysics and biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Patrick Andre
- Portola Pharmaceuticals, Portola Pharmaceuticals, South San Francisco, CA
| | - Pamela B. Conley
- Portola Pharmaceuticals, Portola Pharmaceuticals, South San Francisco, CA
| | - Nigel Mackman
- Mc Allister Heart Institute, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Wolfgang Bergmeier
- Biophysics and biochemistry/ Mc Allister Heart Institute, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
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Stefanini L, Snider A, Piatt R, Petrich B, Bergmeier W. Abstract 42: A Talin Mutant that Disrupts Talin-integrin Binding in Platelets Decelerates aIIbß3 Activation Without Pathological Bleeding. Arterioscler Thromb Vasc Biol 2013. [DOI: 10.1161/atvb.33.suppl_1.a42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tight regulation of integrin affinity is a critical component of hemostasis. The final step of integrin inside-out activation is talin binding to two distinct sites within the integrin β cytoplasmic tail, an NPLY sequence and a membrane-proximal region (MPR). Selective deletion of talin1 from platelets (Tln1fl/flPf4-Cre+) completely prevents integrin activation and thrombus formation, and results in profound defects in hemostasis. Interestingly, platelet-specific expression of a talin1 mutant (L325R) that lacks the ability to bind the MPR, but can still bind the NPLY sequence, phenocopies talin1-knockout platelets. In this study we sought to analyze the effects on thrombosis and hemostasis of a platelet-specific talin1 mutation (W359A) that dramatically impairs binding to the NPLY sequence and does not rescue the talin1 deficiency in transfected cells.
Homozygous knock-in of talin(W359A) is embryonic lethal in mice. Thus, Tln1W359A/wt mice were crossed with Tln1fl/flPf4-Cre+ mice to generate Tln1W359A/flPf4-Cre+ (TlnWA) and Tln1wt/flPf4-Cre+ (Tlnwt) control mice. Expression of talin(W359A) in platelets partially rescued talin1 deficiency. Compared to Tlnwt controls, agonist-induced αIIbβ3 activation was reduced by ~50% and spreading on fibrinogen was only moderately impaired in TlnWA platelets. However, kinetic studies demonstrated decelerated αIIbβ3 activation in TlnWA platelets, which resulted in delayed aggregation under static conditions and reduced thrombus size at low shear rates. Interestingly, adhesion of TlnWA platelets to collagen at high shear rates was not significantly better than that of talin-deficient cells and TlnWA mice were completely protected from FeCl3-induced carotid artery occlusion. Lastly, in contrast to platelet-specific talin-knockout or TlnLR mice, TlnWA mice showed no detectable gastrointestinal bleeding and only modestly increased tail-bleeding times compared to littermate controls.
In conclusion, we demonstrate that the talin(W359A) mutation decelerates, but does not abolish, talin-dependent integrin activation in platelets. Our studies further suggest that this delay in integrin activation is protective from pathological vessel occlusion while it does not affect hemostasis in mice.
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Affiliation(s)
- Lucia Stefanini
- Biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Adam Snider
- Medicine, Univ of California San Diego, La Jolla, CA
| | - Raymond Piatt
- Biochemistry, Univ of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Brian Petrich
- Medicine, Univ of California San Diego, La Jolla, CA
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Kramer M, Matush L, Vanilovich I, Piatt R, Mazer B. Does Breastfeeding Help Prevent Asthma and Allergy? Evidence from a Randomized trial in Belarus. Am J Epidemiol 2006. [DOI: 10.1093/aje/163.suppl_11.s85-d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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