Header

UZH-Logo

Maintenance Infos

Activated protein C-cleaved protease activated receptor-1 is retained on the endothelial cell surface even in the presence of thrombin


Schuepbach, Reto A; Feistritzer, Clemens; Brass, Lawrence F; Riewald, Matthias (2008). Activated protein C-cleaved protease activated receptor-1 is retained on the endothelial cell surface even in the presence of thrombin. Blood, 111(5):2667-2673.

Abstract

Activated protein C (APC) signals in endothelial cells ex vivo through protease activated receptor-1 (PAR1). However, it is controversial whether PAR1 can mediate APC's protective effects in sepsis because the inflammatory response results in thrombin generation and thrombin proteolytically activates PAR1 much more efficiently than APC. Here we show that APC can induce powerful barrier protective responses in an endothelial cell monolayer in the presence of thrombin. Using cell surface immunoassays with conformation sensitive monoclonal anti-PAR1 antibodies we analyzed cleavage of endogenous PAR1 on the endothelial cell surface by APC in the absence and presence of thrombin. Incubation with APC caused efficient PAR1 cleavage and upon coincubation with thrombin APC supported additional PAR1 cleavage. Thrombin-cleaved PAR1 rapidly disappeared from the cell surface whereas, unexpectedly, the APC-cleaved PAR1 remained and could be detected on the cell surface, even when thrombin at concentrations of up to 1 nM was also present. Our findings demonstrate for the first time directly that APC can generate a distinct PAR1 population on endothelial cells in the presence of thrombin. The data suggest that different trafficking of activated PAR1 might explain how PAR1 signaling by APC can be relevant when thrombin is present.

Abstract

Activated protein C (APC) signals in endothelial cells ex vivo through protease activated receptor-1 (PAR1). However, it is controversial whether PAR1 can mediate APC's protective effects in sepsis because the inflammatory response results in thrombin generation and thrombin proteolytically activates PAR1 much more efficiently than APC. Here we show that APC can induce powerful barrier protective responses in an endothelial cell monolayer in the presence of thrombin. Using cell surface immunoassays with conformation sensitive monoclonal anti-PAR1 antibodies we analyzed cleavage of endogenous PAR1 on the endothelial cell surface by APC in the absence and presence of thrombin. Incubation with APC caused efficient PAR1 cleavage and upon coincubation with thrombin APC supported additional PAR1 cleavage. Thrombin-cleaved PAR1 rapidly disappeared from the cell surface whereas, unexpectedly, the APC-cleaved PAR1 remained and could be detected on the cell surface, even when thrombin at concentrations of up to 1 nM was also present. Our findings demonstrate for the first time directly that APC can generate a distinct PAR1 population on endothelial cells in the presence of thrombin. The data suggest that different trafficking of activated PAR1 might explain how PAR1 signaling by APC can be relevant when thrombin is present.

Statistics

Citations

44 citations in Web of Science®
46 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

43 downloads since deposited on 11 Dec 2012
15 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Division of Surgical Intensive Care Medicine
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:2008
Deposited On:11 Dec 2012 17:18
Last Modified:27 Aug 2017 22:39
Publisher:American Society of Hematology
Series Name:Blood
ISSN:0006-4971
Free access at:PubMed ID. An embargo period may apply.
Publisher DOI:https://doi.org/10.1182/blood-2007-09-113076
PubMed ID:18089851

Download

Download PDF  'Activated protein C-cleaved protease activated receptor-1 is retained on the endothelial cell surface even in the presence of thrombin'.
Preview
Filetype: PDF
Size: 859kB
View at publisher