Functional regulation of anticoagulant protein C and clotting factor Va by fibrinolytic plasmin
department or school: Medicine, Faculty of
department or school: Pathology and Laboratory Medicine, Department of
data provider: DSpace
degree campus: UBCV
creator: Lee, Frank Man Hon
issued: 2020-07-22T13:21:29Z
issued: 2020
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Thrombosis is the leading cause of death and disability. Clots (i.e. thrombi) that obstruct blood flow from delivering oxygen and nutrients to tissues require rapid removal. The main treatment is with tissue plasminogen activator (tPA), which activates the enzyme plasmin from its circulating precursor plasminogen. Plasmin works by degrading fibrin, a meshwork of fibers that form the structural scaffold of the clot. Although these thrombolytic drugs have saved countless lives, their use is associated with life-threatening complications including increased bleeding risk and cellular toxicity. By greatly elevating plasmin concentrations with intravenous tPA, the effect of plasmin on its other substrates apart from fibrin may play an important role in dysregulating hemostasis, giving insight into physiological mechanisms that are impacted by thrombolysis. This thesis focuses on the modulatory effects of plasmin on protein C (PC) and activated clotting factor (F) V (FVa). Fragmentation of PC by plasmin assessed in conjunction with activated PC (APC)-specific chromogenic substrate cleavage showed increased amidolytic activity correlating with proteolysis of the PC heavy chain (PC-Hc). Plasmin-cleaved PC inhibited inactivation of FVa and had no appreciable effect on prolonging plasma clotting times in PC-deficient plasma compared with APC. N-terminal sequencing showed that plasmin cleaves PC-Hc within the autolysis loop and at the canonical thrombin activation site. Our findings so far are consistent with natural and engineered APC variants, affected within or adjacent to the autolysis loop, that have reduced anticoagulant function. Interestingly, these mutants still signal through protease-activated receptor 1, suggesting a novel role for plasmin-modulated (A)PC in conferring cytoprotection. For FVa, plasmin-specific cleavage of chromogenic substrate and protein staining were used to confirm the requirement for proteolysis by plasmin in converting FVa into an accelerator …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/75242
note: FUNCTIONAL REGULATION OF ANTICOAGULANT PROTEIN C AND CLOTTING FACTOR Va BY FIBRINOLYTIC PLASMIN by Frank Man Hon Lee B.H.Sc., McMaster University, 2013 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Pathology and Laboratory Medicine) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) July 2020 © Frank Man Hon Lee, 2020 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Functional regulation of anticoagulant protein C and clotting factor Va by fibrinolytic plasmin submitted by Frank Man Hon Lee in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Pathology and Laboratory Medicine Examining Committee: Dr. Edward Pryzdial, Pathology and Laboratory Medicine Supervisor Dr. Edward Conway, Medicine Supervisory Committee Member Dr. David Waisman, Dalhousie University, Pathology External Examiner Dr. Ross MacGillivray, Biochemistry and Molecular Biology University Examiner Dr. Dieter Bromme, Oral Biological and Medical Sciences University Examiner Additional Supervisory Committee Members: Dr. Shannon Jackson, Providence Hematology Supervisory Committee Member Dr. Haydn Pritchard, Pathology and Laboratory Medicine Supervisory Committee Member iii Abstract Thrombosis is the leading cause of death and disability. Clots (i.e. thrombi) that obstruct blood flow from delivering oxygen and nutrients to tissues require rapid removal. The main treatment is with tissue plasminogen activator (tPA), which activates the enzyme plasmin from its circulating precursor plasminogen. Plasmin works by degrading fibrin, a meshwork of fibers that form the structural scaffold of the clot. Although these thrombolytic drugs have saved countless lives, their use is associated with life-threatening complications including increased bleeding risk and cellu…
has type: Thesis/Dissertation
date issued: 2020-11
is shown at: 10.14288/1.0392495
language: eng
degree discipline: Pathology and Laboratory Medicine
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/75242