title: EspP, an Extracellular Serine Protease from Enterohemorrhagic E. coli, Reduces Coagulation Factor Activities, Reduces Clot Strength, and Promotes Clot Lysis.
abstract: BACKGROUND
  EspP (E. coli secreted serine protease, large plasmid encoded) is an extracellular serine protease produced by enterohemorrhagic E. coli (EHEC) O157:H7, a causative agent of diarrhea-associated Hemolytic Uremic Syndrome (D+HUS). The mechanism by which EHEC induces D+HUS has not been fully elucidated.
  
  
  OBJECTIVE
  We investigated the effects of EspP on clot formation and lysis in human blood.
  
  
  METHODS
  Human whole blood and plasma were incubated with EspP(WT )at various concentrations and sampled at various time points. Thrombin time (TT), prothrombin time (PT), and activated partial thromboplastin time (aPTT), coagulation factor activities, and thrombelastgraphy (TEG) were measured.
  
  
  CONCLUSIONS
  Human whole blood or plasma incubated with EspP(WT) was found to have prolonged PT, aPTT, and TT. Furthermore, human whole blood or plasma incubated with EspP(WT) had reduced activities of coagulation factors V, VII, VIII, and XII, as well as prothrombin. EspP did not alter the activities of coagulation factors IX, X, or XI. When analyzed by whole blood TEG, EspP decreased the maximum amplitude of the clot, and increased the clot lysis. Our results indicate that EspP alters hemostasis in vitro by decreasing the activities of coagulation factors V, VII, VIII, and XII, and of prothrombin, by reducing the clot strength and accelerating fibrinolysis, and provide further evidence of a functional role for this protease in the virulence of EHEC and the development of D+HUS.
authors.affiliation: Division of Medical Oncology and Hematology, University Health Network, Toronto, ON, Canada.
authors.forename: Kevin H M
authors.initials: KH
authors.lastname: Kuo
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.|Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON, Canada.
authors.forename: Shekeb
authors.initials: S
authors.lastname: Khan
authors.affiliation: Division of Hematology, Hospital for Sick Children, Toronto, ON, Canada.|Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.|Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Rand
authors.affiliation: Department of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Hira S
authors.initials: HS
authors.lastname: Mian
authors.affiliation: Department of Clinical Pathology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
authors.forename: Elena
authors.initials: E
authors.lastname: Brnjac
authors.affiliation: Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON, Canada.
authors.forename: Linda E
authors.initials: LE
authors.lastname: Sandercock
authors.affiliation: Program in Molecular Structure and Function, The Hospital for Sick Children Research Institute, Toronto, ON, Canada.
authors.forename: Indira
authors.initials: I
authors.lastname: Akula
authors.affiliation: Program in Molecular Structure and Function, The Hospital for Sick Children Research Institute, Toronto, ON, Canada.|Department of Biochemistry, University of Toronto, Toronto, ON, Canada.|Department of Immunology, University of Toronto, Toronto, ON, Canada.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Julien
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.|Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto, ON, Canada.|Department of Biochemistry, University of Toronto, Toronto, ON, Canada.|Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
authors.forename: Emil F
authors.initials: EF
authors.lastname: Pai
authors.affiliation: Department of Clinical Pathology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
authors.forename: Alden E
authors.initials: AE
authors.lastname: Chesney
mesh_terms: D001777:Blood Coagulation / Q000502:physiology*; D001778:Blood Coagulation Disorders / Q000378:metabolism; D001779:Blood Coagulation Factors / Q000378:metabolism*; D054324:Enterohemorrhagic Escherichia coli / Q000378:metabolism*; D019453:Escherichia coli O157 / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism*; D063285:Fibrin Clot Lysis Time / Q000379:methods; D005342:Fibrinolysis / Q000502:physiology; D006463:Hemolytic-Uremic Syndrome / Q000378:metabolism; D006801:Humans; D010314:Partial Thromboplastin Time / Q000379:methods; D011516:Prothrombin / Q000378:metabolism; D011517:Prothrombin Time / Q000379:methods; D012697:Serine Endopeptidases / Q000378:metabolism*; D057057:Serine Proteases / Q000378:metabolism*; D013927:Thrombosis / Q000378:metabolism
chemical_list: D001779:Blood Coagulation Factors; D029968:Escherichia coli Proteins; D011516:Prothrombin; D057057:Serine Proteases; C107189:EspP protein, E coli; D012697:Serine Endopeptidases