Thromb Haemost 2008; 99(01): 44-51
DOI: 10.1160/TH07-08-0495
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Cathepsin G, a leukocyte protease, activates coagulation factor VIII

Andrew J Gale
1   Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
,
Diana Rozenshteyn
1   Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
› Institutsangaben

Financial support: This study was supported by an Early Career Investigator Award from Bayer Healthcare, by a Career Development Award from the National Hemophilia Foundation and by NIH grant HL82588.
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Publikationsverlauf

Received: 06. August 2007

Accepted after major revision: 16. November 2007

Publikationsdatum:
24. November 2017 (online)

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Summary

Neutrophils and monocytes express cathepsin G and can also bind to activated platelets, thus they can be localized to the site of active coagulation. Previous studies have suggested that cathepsin G inactivated coagulation factorVIII (FVIII) and was thus anticoagulant. But other studies have indicated procoagulant functions for cathepsin G in activation of coagulation factorV or activation of platelets among other possible mechanisms. Therefore, it remains unclear if cathepsin G is anticoagulant or procoagulant. We investigated the effects of human neutrophil cathepsin G on FVIII/VIIIa. Cathepsin G activates FVIII to a partially active form while having only a minor inactivating effect on thrombin- activated FVIIIa. This inactivation is mostly due to decreased stability of FVIIIa since a disulfide bond that prevents A2 subunit dissociation from FVIIIa prevents any loss of activity due to cathepsin G proteolysis. FVIII that has been cleaved by cathepsin G can still be activated by thrombin if A2 subunit dissociation is prevented. Cathepsin G cleavages of FVIII are limited to a few specific sites that are mostly located near known activating and inactivating cleavage sites. Cathepsin G cleavage sites near to thrombin cleavage sites likely contribute to the partial activation of FVIII. Therefore, it is possible that cathepsin G from neutrophils and monocytes may provide some pro-coagulant effect by activating FVIII.