Heparin blockade of thrombin-induced smooth muscle cell migration involves inhibition of epidermal growth factor (EGF) receptor transactivation by heparin-binding EGF-like growth factor.
Agonists of G protein-coupled receptors, such as thrombin, act in part by transactivating the epidermal growth factor (EGF) receptor (EGFR). Although at first a ligand-independent mechanism for EGFR transactivation was postulated, it has recently been shown that this transactivation by various G protein-coupled receptor agonists can involve heparin-binding EGF-like growth factor (HB-EGF). Because thrombin stimulation of vascular smooth muscle cell migration is blocked by heparin and because heparin can displace HB-EGF, we investigated the possibility that thrombin stimulation of smooth muscle cells (SMCs) depends on EGFR activation by HB-EGF. In rat SMCs, EGFR phosphorylation and extracellular signal-regulated kinase (ERK) activation in response to thrombin are inhibited not only by the EGFR inhibitor AG1478 and by EGFR blocking antibody but also by heparin and by neutralizing HB-EGF antibody. HB-EGF-dependent signaling induced by thrombin is inhibited by batimastat, which suggests a requirement for pro-HB-EGF shedding by a metalloproteinase. We further demonstrate that this novel pathway is required for the migration of rat and baboon SMCs in response to thrombin. We conclude from these data that the inhibitory effect of heparin on SMC migration induced by thrombin relies, at least in part, on a blockade of HB-EGF-mediated EGFR transactivation.
Kalmes
A
A
Department of Surgery, University of Washington, Seattle 98195-6410, USA. kalmes@u.washington.edu
Vesti
B R
BR
Daum
G
G
Abraham
J A
JA
Clowes
A W
AW
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D001011:Aorta; D000077214:Becaplermin; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010215:Papio; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000494:pharmacology; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D011799:Quinazolines; D051381:Rats; D011916:Rats, Inbred F344; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013876:Thiophenes / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology* / Q000502:physiology; D020032:Tyrphostins / Q000494:pharmacology
D000925:Anticoagulants; C587883:HBEGF protein, human; C587885:Hbegf protein, rat; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D010982:Platelet-Derived Growth Factor; D011480:Protease Inhibitors; D020574:Proto-Oncogene Proteins c-sis; D011799:Quinazolines; D013876:Thiophenes; D020032:Tyrphostins; C101044:RTKI cpd; D000077214:Becaplermin; D010649:Phenylalanine; D004815:Epidermal Growth Factor; D006493:Heparin; C080985:batimastat; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; D013917:Thrombin