Protease-mediated human smooth muscle cell proliferation by urokinase requires epidermal growth factor receptor transactivation by triple membrane signaling

Enrico A. Duru, Yuyang Fu, Mark G. Davies

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Background: Urokinase (uPA) modulates cellular and extracellular matrix responses within the microenvironment of the vessel wall and has been shown to activate the epidermal growth factor receptor (EGFR). This study examines the role of the protease domain of uPA during EGFR activation in human vascular smooth muscle cells (VSMC). Methods: Human coronary VSMC were cultured in vitro. Assays of cell proliferation and EGFR phosphorylation were examined in response to the carboxyterminal fragment of uPA (CTF) in the presence and absence of the plasmin, metalloprotease and a disintegrin and metalloproteinase (ADAM) inhibitors, heparin-bound epidermal growth factor (HB-EGF), and EGFR inhibitors, and small interfering RNA to EGFR and ADAMs. Results: CTF produced a dose-dependent increase in DNA synthesis and cell proliferation in human VSMC, which was blocked in a dose-dependent manner by both plasmin inhibitors and the EGFR inhibitor, AG1478. CTF induced time-dependent EGFR phosphorylation, which was blocked by inhibitors of plasmin and metalloproteinases activity. The presence of urokinase plasminogen activator receptor was not required. Inhibition of ADAM-10 and -12, and of HB-EGF blocked EGFR activation in response to CTF. CTF-mediated activation of EGFR was mediated through Gβγ, src, and NAD(P)H oxidase. Conclusions: In human coronary VSMC, uPA induces uPAR-independent, domain-dependent smooth muscle cell proliferation through transactivation of EGFR by a plasmin-mediated, ADAM-induced, and HB-EGF - dedependent process, which is mediated by the intracellular pathways involving Gαi, Gβγ, src, and NAD(P)H oxidase.

Original languageEnglish (US)
Pages (from-to)254-262
Number of pages9
JournalJournal of Surgical Research
Volume192
Issue number2
DOIs
StatePublished - Dec 1 2014

Keywords

  • Cell signaling
  • Epidermal growth factor receptor
  • Human coronary smooth muscle cell
  • Proliferation
  • Protease domain
  • uPA

ASJC Scopus subject areas

  • Surgery

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