title: PDK1 Determines Collagen-Dependent Platelet Ca2+ Signaling and Is Critical to Development of Ischemic Stroke In Vivo.
abstract: Activation of platelets by subendothelial collagen results in an increase of cytosolic Ca(2+) concentration ([Ca(2+)]i) and is followed by platelet activation and thrombus formation that may lead to vascular occlusion. The present study determined the role of phosphoinositide-dependent protein kinase 1 (PDK1) in collagen-dependent platelet Ca(2+) signaling and ischemic stroke in vivo.
  
  
  
  Platelet activation with collagen receptor glycoprotein VI agonists collagen-related peptide or convulxin resulted in a significant increase in PDK1 activity independent of second-wave signaling. PDK1 deficiency was associated with reduced platelet phospholipase Cγ2-dependent inositol-1,4,5-trisphosphate production and intracellular [Ca(2+)]i in response to stimulation with collagen-related peptide or convulxin. The defective increase of [Ca(2+)]i resulted in a substantial defect in activation-dependent platelet secretion and aggregation on collagen-related peptide stimulation. Furthermore, Rac1 activation and spreading, adhesion to collagen, and thrombus formation under high arterial shear rates were significantly diminished in PDK1-deficient platelets. Mice with PDK1-deficient platelets were protected against arterial thrombotic occlusion after FeCl3-induced mesenteric arterioles injury and ischemic stroke in vivo. These mice had significantly reduced brain infarct volumes, with a significantly increased survival of 7 days after transient middle cerebral artery occlusion without increase of intracerebral hemorrhage. Tail bleeding time was prolonged in pdk1(-/-) mice, reflecting an important role of PDK1 in primary hemostasis.
  
  
  
  PDK1 is required for Ca(2+)-dependent platelet activation on stimulation of collagen receptor glycoprotein VI, arterial thrombotic occlusion, and ischemic stroke in vivo.
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Patrick
authors.initials: P
authors.lastname: Münzer
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Britta
authors.initials: B
authors.lastname: Walker-Allgaier
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Sascha
authors.initials: S
authors.lastname: Geue
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Eva
authors.initials: E
authors.lastname: Geuss
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Gregor
authors.initials: G
authors.lastname: Hron
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Dominik
authors.initials: D
authors.lastname: Rath
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Daniela
authors.initials: D
authors.lastname: Eißler
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Stefan
authors.initials: S
authors.lastname: Winter
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Elke
authors.initials: E
authors.lastname: Schaeffeler
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Monika
authors.initials: M
authors.lastname: Meinert
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Martin
authors.initials: M
authors.lastname: Schaller
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Andreas
authors.initials: A
authors.lastname: Greinacher
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Matthias
authors.initials: M
authors.lastname: Schwab
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Tobias
authors.initials: T
authors.lastname: Geisler
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Christoph
authors.initials: C
authors.lastname: Kleinschnitz
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.).
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.). oliver.borst@med.uni-tuebingen.de meinrad.gawaz@med.uni-tuebingen.de.
authors.forename: Meinrad
authors.initials: M
authors.lastname: Gawaz
authors.affiliation: From the Department of Cardiology and Cardiovascular Medicine (P.M., B.W.-A., S.G., D.R., D.E., T.G., M.G., O.B.), Department of Physiology (B.W.-A., F.L.), Department of Evolutionary Biology of Invertebrates, Institute for Evolution and Ecology (M.M.), Department of Dermatology (M.S.), and Department of Clinical Pharmacology (M.S.), University of Tübingen, Tübingen, Germany; Department of Neurology, University of Würzburg, Würzburg, Germany (E.G., C.K.); Institute for Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany (G.H., A.G.); and Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen, Germany (S.W., E.S., M.S.). oliver.borst@med.uni-tuebingen.de meinrad.gawaz@med.uni-tuebingen.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Borst
mesh_terms: D064413:3-Phosphoinositide-Dependent Protein Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001792:Blood Platelets / Q000201:enzymology*; D020013:Calcium Signaling; D003094:Collagen / Q000378:metabolism*; D004195:Disease Models, Animal; D020022:Genetic Predisposition to Disease; D020244:Infarction, Middle Cerebral Artery / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D015544:Inositol 1,4,5-Trisphosphate / Q000097:blood; D018345:Mice, Knockout; D009479:Neuropeptides / Q000097:blood; D010641:Phenotype; D051966:Phospholipase C gamma / Q000097:blood; D015539:Platelet Activation; D010973:Platelet Adhesiveness; D010974:Platelet Aggregation; D010980:Platelet Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics; D013927:Thrombosis / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D013997:Time Factors; D020830:rac1 GTP-Binding Protein / Q000097:blood
chemical_list: D009479:Neuropeptides; D010980:Platelet Membrane Glycoproteins; C484602:Rac1 protein, mouse; C098341:platelet membrane glycoprotein VI; D015544:Inositol 1,4,5-Trisphosphate; D003094:Collagen; D064413:3-Phosphoinositide-Dependent Protein Kinases; C578564:Pdpk1 protein, mouse; D051966:Phospholipase C gamma; D020830:rac1 GTP-Binding Protein
keywords: Ca2+ signaling; PDK1; PLCγ2; ischemic stroke; platelets