title: Redundant functions of phospholipases D1 and D2 in platelet α-granule release.
abstract: BACKGROUND
  Platelet activation and aggregation are crucial for primary hemostasis, but can also result in occlusive thrombus formation. Agonist-induced platelet activation involves different signaling pathways leading to the activation of phospholipases, which produce second messengers. The role of phospholipase C (PLC) in platelet activation is well established, but less is known about the relevance of phospholipase D (PLD).
  
  
  OBJECTIVE
  The aim of this study was to determine a potential function of PLD2 in platelet physiology. Thus, we investigated the function of PLD2 in platelet signaling and thrombus formation, by generating mice lacking PLD2 or both PLD1 and PLD2. Adhesion, activation and aggregation of PLD-deficient platelets were analyzed in vitro and in vivo.
  
  
  RESULTS
  Whereas the absence of PLD2 resulted in reduced PLD activity in platelets, it had no detectable effect on the function of the cells in vitro and in vivo. However, the combined deficiency of both PLD isoforms resulted in defective α-granule release and protection in a model of FeCl3 -induced arteriolar thrombosis, effects that were not observed in mice lacking only one PLD isoform.
  
  
  CONCLUSIONS
  These results reveal redundant roles of PLD1 and PLD2 in platelet α-granule secretion, and indicate that this may be relevant for pathologic thrombus formation.
authors.affiliation: Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg Department of Neurology, University of Würzburg, Würzburg Biocenter, University of Würzburg, Würzburg, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Thielmann
authors.forename: D
authors.initials: D
authors.lastname: Stegner
authors.forename: P
authors.initials: P
authors.lastname: Kraft
authors.forename: I
authors.initials: I
authors.lastname: Hagedorn
authors.forename: G
authors.initials: G
authors.lastname: Krohne
authors.forename: C
authors.initials: C
authors.lastname: Kleinschnitz
authors.forename: G
authors.initials: G
authors.lastname: Stoll
authors.forename: B
authors.initials: B
authors.lastname: Nieswandt
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D001011:Aorta / Q000473:pathology; D001760:Bleeding Time; D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism*; D002448:Cell Adhesion; D003433:Crosses, Genetic; D005260:Female; D006487:Hemostasis; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010739:Phospholipase D / Q000502:physiology*; D015539:Platelet Activation; D010978:Platelet Factor 4 / Q000737:chemistry; D015398:Signal Transduction; D013927:Thrombosis / Q000503:physiopathology; D014841:von Willebrand Factor / Q000737:chemistry
chemical_list: D014841:von Willebrand Factor; D010978:Platelet Factor 4; D000255:Adenosine Triphosphate; C105606:phospholipase D2; D010739:Phospholipase D; C106801:phospholipase D1