title: Recombinant human activated protein C upregulates the release of soluble fractalkine from human endothelial cells.
abstract: Fractalkine is a unique endothelial cell-derived chemokine that functions both as a chemoattractant and as an adhesion molecule. Recent findings suggest that fractalkine plays an important role in inflammatory diseases by modulating leucocyte endothelial cell interactions. A modulating effect on the immune system in severe sepsis has been suggested for recombinant human activated protein C (rhAPC). However, a little is known about the effect of rhAPC on the endothelial release of soluble fractalkine. The effect of rhAPC (50 ng/ml to 10 microg/ml) and protein C (in equimolar concentrations) on the synthesis of fraktalkine-mRNA and release of soluble protein in human umbilical vein endothelial cells (HUVEC) was determined by reverse transcription-polymerase chain reaction and by an enzyme-linked immunosorbent assay. rhAPC at supra-pharmacological concentrations (1-10 microg/ml) stimulated fractalkine-messenger RNA-gene transcription and release of soluble fractalkine in a time- and dose-dependent manner, whereas the zymogen protein C was ineffective. As shown by experiments using monoclonal antibodies against the thrombin receptor, protease-activated receptor-1 (PAR-1), PAR-2 and against the endothelial protein C receptor (EPCR), the effect of rhAPC on fractalkine upregulation was mediated by binding to the EPCR-receptor and signalling via PAR-1. These in vitro data demonstrate that induction of fractalkine release is an important response of HUVEC to stimulation with rhAPC and may lead to a better understanding of the molecular pathways involved in the mode of action of rhAPC. Further clinical trials are needed to confirm the in vivo relevance of these data.
authors: 1st Department of Medicine, Faculty of Clinical Medicine Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany. martina.brueckmann@med.ma.uni-heidelberg.de
authors: Martina
authors: M
authors: Brueckmann
authors: Adriane Schulze
authors: AS
authors: Nahrup
authors: Siegfried
authors: S
authors: Lang
authors: Thomas
authors: T
authors: Bertsch
authors: Kenji
authors: K
authors: Fukudome
authors: Volker
authors: V
authors: Liebe
authors: Jens J
authors: JJ
authors: Kaden
authors: Ursula
authors: U
authors: Hoffmann
authors: Martin
authors: M
authors: Borggrefe
authors: Guenter
authors: G
authors: Huhle