3
|
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: 1.9] [Reference Citation Analysis] [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.
Collapse
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.
| |
Collapse
|
5
|
Jandrey KE, Norris JW, Tucker M, Brooks MB. Clinical characterization of canine platelet procoagulant deficiency (Scott syndrome). J Vet Intern Med 2012; 26:1402-7. [PMID: 23061683 DOI: 10.1111/j.1939-1676.2012.01012.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 06/26/2012] [Accepted: 08/28/2012] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Platelet function defects are rare causes of bleeding diatheses; however, disease prevalence might be underestimated because diagnosis requires assessment of specific parameters of platelet activation. OBJECTIVES The goal of this study was to characterize the clinical presentation of canine Scott syndrome (CSS), an intrinsic platelet function defect first identified in a closed colony of German Shepherds (GSD). ANIMALS Eleven (n = 6 female) client-owned GSD affected with CSS that sought veterinary care for one or more episodes of abnormal bleeding. METHODS Retrospective review of all cases of CSS diagnosed through the Comparative Coagulation Laboratory at Cornell University between 2005 and 2011. The diagnosis of CSS was based on 2 measures of platelet procoagulant activity: serum prothrombin consumption and flow cytometric detection of platelet phosphatidylserine externalization after in vitro activation. RESULTS Postoperative hemorrhage was the most common sign of CSS, whereas petechiae were not found in any dog. Although most GSD responded to platelet transfusion, refractory epistaxis in 2 GSD was managed by nasal arterial embolization. The CSS trait was not restricted to a single pedigree of related GSD or to a single geographic region. CONCLUSIONS AND CLINICAL IMPORTANCE Unlike thrombocytopenia and platelet aggregation defects, petechiae and other capillary hemorrhage are not typical features of CSS. After preliminary screening to rule out more common causes of hemorrhage, CSS should be considered in the differential diagnosis of recurrent hemorrhage in GSD, and potentially other breeds of dog. Definitive diagnosis of CSS requires specific tests of platelet procoagulant activity.
Collapse
Affiliation(s)
- K E Jandrey
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | | | | | | |
Collapse
|
7
|
Goggs R, Poole AW. Platelet signaling-a primer. J Vet Emerg Crit Care (San Antonio) 2012; 22:5-29. [PMID: 22316389 DOI: 10.1111/j.1476-4431.2011.00704.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 11/25/2011] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To review the receptors and signal transduction pathways involved in platelet plug formation and to highlight links between platelets, leukocytes, endothelium, and the coagulation system. DATA SOURCES Original studies, review articles, and book chapters in the human and veterinary medical fields. DATA SYNTHESIS Platelets express numerous surface receptors. Critical among these are glycoprotein VI, the glycoprotein Ib-IX-V complex, integrin α(IIb) β(3) , and the G-protein-coupled receptors for thrombin, ADP, and thromboxane. Activation of these receptors leads to various important functional events, in particular activation of the principal adhesion receptor α(IIb) β(3) . Integrin activation allows binding of ligands such as fibrinogen, mediating platelet-platelet interaction in the process of aggregation. Signals activated by these receptors also couple to 3 other important functional events, secretion of granule contents, change in cell shape through cytoskeletal rearrangement, and procoagulant membrane expression. These processes generate a stable thrombus to limit blood loss and promote restoration of endothelial integrity. CONCLUSIONS Improvements in our understanding of how platelets operate through their signaling networks are critical for diagnosis of unusual primary hemostatic disorders and for rational antithrombotic drug design.
Collapse
Affiliation(s)
- Robert Goggs
- School of Physiology and Pharmacology, Faculty of Medical and Veterinary Sciences, University of Bristol, UK.
| | | |
Collapse
|
10
|
Brooks M, Etter K, Catalfamo J, Brisbin A, Bustamante C, Mezey J. A genome-wide linkage scan in German shepherd dogs localizes canine platelet procoagulant deficiency (Scott syndrome) to canine chromosome 27. Gene 2010; 450:70-5. [PMID: 19854246 PMCID: PMC3064881 DOI: 10.1016/j.gene.2009.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 09/12/2009] [Accepted: 09/16/2009] [Indexed: 11/26/2022]
Abstract
Scott syndrome is a rare hereditary bleeding disorder associated with an inability of stimulated platelets to externalize the negatively charged phospholipid, phosphatidylserine (PS). Canine Scott syndrome (CSS) is the only naturally occurring animal model of this defect and therefore represents a unique tool to discover a disease gene capable of producing this platelet phenotype. We undertook platelet function studies and linkage analyses in a pedigree of CSS-affected German shepherd dogs. Based on residual serum prothrombin and flow cytometric assays, CSS segregates as an autosomal recessive trait. An initial genome scan, performed by genotyping 48 dogs for 280 microsatellite markers, suggested linkage with markers on chromosome 27. Genotypes ultimately obtained for a total of 56 dogs at 11 markers on chromosome 27 revealed significant LOD scores for 2 markers near the centromere, with multipoint linkage indicating a CSS trait locus spanning approximately 14 cm. These results provide the basis for fine mapping studies to narrow the disease interval and target the evaluation of putative disease genes.
Collapse
Affiliation(s)
- Marjory Brooks
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
| | | | | | | | | | | |
Collapse
|