title: Antihemostatic activity of human granzyme B mediated by cleavage of von Willebrand factor.
abstract: The cytotoxic lymphocyte protease granzyme B (GrB) is elevated in the plasma of individuals with diseases that elicit a cytotoxic lymphocyte-mediated immune response. Given the recently recognized ability of GrB to cleave extracellular matrix proteins, we examined the effect of GrB on the pro-hemostatic molecule von Willebrand factor (VWF). GrB delays ristocetin-induced platelet aggregation and inhibits platelet adhesion and spreading on immobilized VWF under static conditions. It efficiently cleaves VWF at two sites within the A1-3 domains that are essential for the VWF-platelet interaction. Like the VWF regulatory proteinase ADAMTS-13, GrB-mediated cleavage is dependent upon VWF conformation. In vitro, GrB cannot cleave the VWF conformer found in solution, but cleavage is induced when VWF is artificially unfolded or presented as a matrix. GrB cleaves VWF with comparable efficiency to ADAMTS-13 and rapidly processes ultra-large VWF multimers released from activated endothelial cells under physiological shear. GrB also cleaves the matrix form of fibrinogen at several sites. These studies suggest extracellular GrB may help control localized coagulation during inflammation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Victoria, Australia.
authors.forename: Marguerite S
authors.initials: MS
authors.lastname: Buzza
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Dyson
authors.forename: Hiuwan
authors.initials: H
authors.lastname: Choi
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Gardiner
authors.forename: Robert K
authors.initials: RK
authors.lastname: Andrews
authors.forename: Dion
authors.initials: D
authors.lastname: Kaiserman
authors.forename: Christina A
authors.initials: CA
authors.lastname: Mitchell
authors.forename: Michael C
authors.initials: MC
authors.lastname: Berndt
authors.forename: Jing-Fei
authors.initials: JF
authors.lastname: Dong
authors.forename: Phillip I
authors.initials: PI
authors.lastname: Bird
mesh_terms: D000818:Animals; D004730:Endothelium, Vascular / Q000502:physiology; D005340:Fibrinogen / Q000502:physiology; D053804:Granzymes / Q000494:pharmacology*; D006487:Hemostasis / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D008222:Lymphokines / Q000502:physiology; D051379:Mice; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects*; D011817:Rabbits; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D008222:Lymphokines; C034397:chemotactic inhibitory factor; D014841:von Willebrand Factor; D005340:Fibrinogen; D053804:Granzymes