Copyright © 2006, European Society of Cardiology
Novel Nox inhibitor VAS2870 attenuates PDGF-dependent smooth muscle cell chemotaxis, but not proliferation
aKlinik III für Innere Medizin der Universität zu Köln, Germany
bVasopharm BIOTECH GmbH, Würzburg, Germany
cInstitut für Physiologie der Universität zu Köln, Germany
dInstitut für Physiologie der Universität Giessen, Germany
eCenter for Molecular Medicine, University of Cologne (CMMC), Germany
* Corresponding author. Klinik III für Innere Medizin, Universität zu Köln, Kerpener Str. 62; 50924 Köln, Germany. Tel.: +49 221 478 5159; fax: +49 221 478 6490. Email address: stephan.rosenkranz{at}uk-koeln.de
Objective Reactive oxygen species (ROS) produced by NAD(P)H oxidases (Nox) play a significant role in the pathophysiology of cardiovascular diseases. Expression and activity of NAD(P)H oxidases are regulated by growth factors such as angiotensin II and platelet-derived growth factor (PDGF). We characterized the effects of the novel Nox inhibitor VAS2870 on PDGF-dependent ROS liberation and cellular events in vascular smooth muscle cells (VSMC).
Methods and results PDGF-BB increased NAD(P)H oxidase activity (lucigenin-enhanced chemiluminescence) and intracellular ROS levels (detected by confocal laserscanning microscopy using 2,7-DCF) to 229±9% and 362±54% at 1 and 2 h, respectively. Preincubation with VAS2870 (10 and 20 µM) completely abolished PDGF-mediated NAD(P)H oxidase activation and ROS production. Since ROS are involved in various growth factor-induced cellular functions, the influence of VAS2870 on PDGF-induced DNA synthesis and chemotaxis was determined. PDGF promoted a 4.2±0.2-fold increase of VSMC migration (modified Boyden chamber, p<0.01) and increased DNA synthesis by maximally 3.2±0.4-fold (BrdU incorporation, p<0.01) in a concentration-dependent manner. Preincubation with VAS2870 (0.1–20 µM) did not affect PDGF-induced cell cycle progression. However, it abolished PDGF-dependent chemotaxis of VSMC in a concentration-dependent manner (100% inhibition at 10 µM). These findings were related to PDGF-dependent signaling events. Western blot analyses using phospho-specific antibodies revealed that the downstream signaling molecules Akt, Erk, and Src were activated by PDGF. However, VAS2870 blocked PDGF-dependent activation of Src, but not of Akt and Erk, in a concentration-dependent manner.
Conclusions VAS2870 effectively suppresses growth factor-mediated ROS liberation in VSMC. Furthermore, it completely inhibits PDGF-dependent VSMC migration, whereas it does not affect DNA synthesis. These divergent effects reflect the critical role of Src activity, which–in contrast to Akt and Erk–appears to be redox-sensitive and is absolutely required for PDGF-induced chemotaxis, but not cell cycle progression.
KEYWORDS NAD(P)H oxidase; Src; Atherosclerosis; Platelet-derived growth factor; ROS
Time for primary review 23 days
This paper was handled by special Guest Editor Andrew C. Newby, Bristol, UK.
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