gms | German Medical Science

27. Wissenschaftlicher Kongress der Deutschen Hochdruckliga

Deutsche Liga zur Bekämpfung des hohen Blutdrucks – Deutsche Hypertonie Gesellschaft e. V.

26. bis 29.11.2003, Bonn

PDGF receptor is required for uPA-induced signalling, migration and proliferation of human vascular smooth muscle cells

Die uPA-induzierte Migration von VSMC wird durch den PDgF-Rezeptor vermittelt

Meeting Abstract (Hypertonie 2003)

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  • presenting/speaker I. Kiian - Medizinische Hochschule Hannover (Hannover, D)
  • I. Dumler - Medizinische Hochschule Hannover (Hannover, D)
  • H. Haller - Medizinische Hochschule Hannover (Hannover, D)

Hypertonie 2003. 27. Wissenschaftlicher Kongress der Deutschen Hochdruckliga. Bonn, 26.-29.11.2003. Düsseldorf, Köln: German Medical Science; 2004. Doc03hochP92

The electronic version of this article is the complete one and can be found online at:

Published: November 11, 2004

© 2004 Kiian et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



In human vascular smooth muscle cell (VSMC), the Jak/Stat signaling pathway is considered as the main signaling cascade activated in response to uPA with functional consequences for cell migration and proliferation. We demonstrated recently that the Tyk2-PI3-K-RhoA-Rho kinase pathway is required for VSMC migration, whereas activation and nuclear translocation of STAT1 mediates uPA-dependent changes of VSMC proliferation. However, it remained unknown how these two cascades are linked to uPAR and which molecules serve for a downstream bifurcation of both pathways. Here we provide evidence that in VSMC platelet-derived growth factor receptor (PDGFR) serves as a transmembrane adaptor for uPAR.

We demonstrate that PDGFR tyrosine kinase activity is required for uPA to promote both, promigratory and profilerative effects. Thus, inhibition of PDGFR tyrosine kinase activity with specific inhibitor AG 1295 dose-dependently inhibited uPA-induced VSMC migration and proliferation. Further, we demonstrate that uPAR and PDGFR in VSMC are associated in a uPA-dependent manner. Thus, uPAR co-immunoprecipitated time-dependently with PDGFR from lysates of uPA stimulated VSMC but not from unstimulated cells. Similar results were obtained by co-immunoprecipitating PDGFR using anti-uPAR antibodies. PDGFR tyrosine kinase is required also for the uPA-induced STAT1 tyrosine and serine phosphorylation,as observed in Western blots. It is likely that PDGFR is capable to phosphorylate STAT1 directly, as far as in immunoprecipitation experiments we found STAT1 to be uPA-dependently associated with PDGFR in VSMC. Addition of uPA (10nM) decreased the PDGF(5ng/ml)-induced VSMC migration in Boyden chamber thus suggesting that uPAR can concure for PDGFR in order to induce uPA-dependent signaling.

Taken together, these findings suggest that PDGFR is involved in regulation of uPA-induced signaling and functional behaviour of human VSMC and can serve as a transmembrane adaptor of uPAR.