Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.

VEGF proteolysis by plasmin or matrix metalloproteinases (MMPs) is believed to play an important role in regulating vascular patterning in vivo by releasing VEGF from the extracellular matrix (ECM). However, a quantitative understanding of the kinetics of VEGF cleavage and the efficiency of cell-med...

Full description

Bibliographic Details
Main Authors: Prakash Vempati, Feilim Mac Gabhann, Aleksander S Popel
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2010-07-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC2912330?pdf=render
_version_ 1818561698190065664
author Prakash Vempati
Feilim Mac Gabhann
Aleksander S Popel
author_facet Prakash Vempati
Feilim Mac Gabhann
Aleksander S Popel
author_sort Prakash Vempati
collection DOAJ
description VEGF proteolysis by plasmin or matrix metalloproteinases (MMPs) is believed to play an important role in regulating vascular patterning in vivo by releasing VEGF from the extracellular matrix (ECM). However, a quantitative understanding of the kinetics of VEGF cleavage and the efficiency of cell-mediated VEGF release is currently lacking. To address these uncertainties, we develop a molecular-detailed quantitative model of VEGF proteolysis, used here in the context of an endothelial sprout.To study a cell's ability to cleave VEGF, the model captures MMP secretion, VEGF-ECM binding, VEGF proteolysis from VEGF165 to VEGF114 (the expected MMP cleavage product of VEGF165) and VEGF receptor-mediated recapture. Using experimental data, we estimated the effective bimolecular rate constant of VEGF165 cleavage by plasmin to be 328 M(-1) s(-1) at 25 degrees C, which is relatively slow compared to typical MMP-ECM proteolysis reactions. While previous studies have implicated cellular proteolysis in growth factor processing, we show that single cells do not individually have the capacity to cleave VEGF to any appreciable extent (less than 0.1% conversion). In addition, we find that a tip cell's receptor system will not efficiently recapture the cleaved VEGF due to an inability of cleaved VEGF to associate with Neuropilin-1.Overall, VEGF165 cleavage in vivo is likely to be mediated by the combined effect of numerous cells, instead of behaving in a single-cell-directed, autocrine manner. We show that heparan sulfate proteoglycans (HSPGs) potentiate VEGF cleavage by increasing the VEGF clearance time in tissues. In addition, we find that the VEGF-HSPG complex is more sensitive to proteases than is soluble VEGF, which may imply its potential relevance in receptor signaling. Finally, according to our calculations, experimentally measured soluble protease levels are approximately two orders of magnitude lower than that needed to reconcile levels of VEGF cleavage seen in pathological situations.
first_indexed 2024-12-14T00:54:15Z
format Article
id doaj.art-7141ac008a1c4ff78c3088ec1edaae13
institution Directory Open Access Journal
issn 1932-6203
language English
last_indexed 2024-12-14T00:54:15Z
publishDate 2010-07-01
publisher Public Library of Science (PLoS)
record_format Article
series PLoS ONE
spelling doaj.art-7141ac008a1c4ff78c3088ec1edaae132022-12-21T23:23:40ZengPublic Library of Science (PLoS)PLoS ONE1932-62032010-07-0157e1186010.1371/journal.pone.0011860Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.Prakash VempatiFeilim Mac GabhannAleksander S PopelVEGF proteolysis by plasmin or matrix metalloproteinases (MMPs) is believed to play an important role in regulating vascular patterning in vivo by releasing VEGF from the extracellular matrix (ECM). However, a quantitative understanding of the kinetics of VEGF cleavage and the efficiency of cell-mediated VEGF release is currently lacking. To address these uncertainties, we develop a molecular-detailed quantitative model of VEGF proteolysis, used here in the context of an endothelial sprout.To study a cell's ability to cleave VEGF, the model captures MMP secretion, VEGF-ECM binding, VEGF proteolysis from VEGF165 to VEGF114 (the expected MMP cleavage product of VEGF165) and VEGF receptor-mediated recapture. Using experimental data, we estimated the effective bimolecular rate constant of VEGF165 cleavage by plasmin to be 328 M(-1) s(-1) at 25 degrees C, which is relatively slow compared to typical MMP-ECM proteolysis reactions. While previous studies have implicated cellular proteolysis in growth factor processing, we show that single cells do not individually have the capacity to cleave VEGF to any appreciable extent (less than 0.1% conversion). In addition, we find that a tip cell's receptor system will not efficiently recapture the cleaved VEGF due to an inability of cleaved VEGF to associate with Neuropilin-1.Overall, VEGF165 cleavage in vivo is likely to be mediated by the combined effect of numerous cells, instead of behaving in a single-cell-directed, autocrine manner. We show that heparan sulfate proteoglycans (HSPGs) potentiate VEGF cleavage by increasing the VEGF clearance time in tissues. In addition, we find that the VEGF-HSPG complex is more sensitive to proteases than is soluble VEGF, which may imply its potential relevance in receptor signaling. Finally, according to our calculations, experimentally measured soluble protease levels are approximately two orders of magnitude lower than that needed to reconcile levels of VEGF cleavage seen in pathological situations.http://europepmc.org/articles/PMC2912330?pdf=render
spellingShingle Prakash Vempati
Feilim Mac Gabhann
Aleksander S Popel
Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.
PLoS ONE
title Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.
title_full Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.
title_fullStr Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.
title_full_unstemmed Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.
title_short Quantifying the proteolytic release of extracellular matrix-sequestered VEGF with a computational model.
title_sort quantifying the proteolytic release of extracellular matrix sequestered vegf with a computational model
url http://europepmc.org/articles/PMC2912330?pdf=render
work_keys_str_mv AT prakashvempati quantifyingtheproteolyticreleaseofextracellularmatrixsequesteredvegfwithacomputationalmodel
AT feilimmacgabhann quantifyingtheproteolyticreleaseofextracellularmatrixsequesteredvegfwithacomputationalmodel
AT aleksanderspopel quantifyingtheproteolyticreleaseofextracellularmatrixsequesteredvegfwithacomputationalmodel