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Published on: May 24, 2024
Cathepsin G, a leukocyte protease, activates coagulation factor VIII
Andrew J Gale1, Diana Rozenshteyn
1Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA. agale@scripps.edu
Thrombosis and Haemostasis
|January 25, 2008
Summary
Cathepsin G from neutrophils and monocytes may promote blood clotting. This enzyme partially activates coagulation factor VIII (FVIII), potentially contributing to a procoagulant effect at sites of active coagulation.
Area of Science:
- Hematology
- Biochemistry
- Cell Biology
Background:
- Neutrophils and monocytes express cathepsin G, an enzyme implicated in coagulation.
- Previous research presents conflicting evidence on whether cathepsin G is anticoagulant or procoagulant.
- The precise role of cathepsin G in coagulation factor VIII (FVIII) regulation remains unclear.
Purpose of the Study:
- To investigate the impact of human neutrophil cathepsin G on coagulation factor VIII (FVIII) and its activated form, FVIIIa.
- To elucidate the mechanisms by which cathepsin G influences FVIII/FVIIIa activity and stability.
Main Methods:
- Purification of human neutrophil cathepsin G.
- Biochemical assays to assess the effects of cathepsin G on FVIII and thrombin-activated FVIIIa.
- Analysis of FVIII cleavage sites and FVIIIa stability following cathepsin G treatment.
Main Results:
- Cathepsin G partially activates FVIII to a semi-active form.
- Cathepsin G exhibits minimal inactivation of thrombin-activated FVIIIa, primarily due to reduced FVIIIa stability.
- Prevention of A2 subunit dissociation protects FVIIIa from cathepsin G-induced activity loss.
- Cathepsin G cleaves FVIII at specific sites, some near known thrombin cleavage sites, contributing to partial FVIII activation.
Conclusions:
- Cathepsin G's interaction with FVIII suggests a potential procoagulant role.
- Neutrophil and monocyte-derived cathepsin G may contribute to clot formation by activating FVIII.
- Understanding cathepsin G's function in coagulation is crucial for managing hemostatic disorders.
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