Published ahead of print on June 10, 2004, doi:10.1165/rcmb.2004-0098OC
© 2004 American Thoracic Society DOI: 10.1165/rcmb.2004-0098OC Src Kinase Mediates Angiotensin II–Dependent Increase in Pulmonary Endothelial Nitric Oxide SynthaseDepartment of Biochemistry and Molecular Biology and Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York Address correspondence to: Susan C. Olson, Ph.D., Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595. E-mail: Susan_Olson{at}nymc.edu We have previously demonstrated that angiotensin II (Ang II) stimulates nitric oxide (NO) production in bovine pulmonary artery endothelial cells (BPAECs) by increasing NO synthase (NOS) expression via the type 2 receptor. The purpose of this study was to identify the Ang II–dependent signaling pathway that mediates this increase in endothelial NOS (eNOS). The Ang II–dependent increase in eNOS expression is prevented when BPAECs are pretreated with the tyrosine kinase inhibitors, herbimycin A and 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-D]pyrimidine, which also blocked Ang II–dependent mitogen-activated protein kinase (MAPK) kinase/extracellular-regulated protein kinase (MEK)-1 and MAPK phosphorylation, suggesting that Src is upstream of MAPK in this pathway. Transfection of BPAECs with an Src dominant negative mutant cDNA prevented the Ang II–dependent Src activation and increase in eNOS protein expression. PD98059, a MEK-1 inhibitor, prevented the Ang II–dependent phosphorylation of extracellular-regulated protein kinases 1 and 2 and increase in eNOS expression. Neither AG1478, an epidermal growth factor receptor kinase inhibitor, nor AG1295, a platelet derived growth factor receptor kinase inhibitor, had any effect on Ang II–stimulated Src activity, MAPK activation, or eNOS expression. Pertussis toxin prevented the Ang II–dependent increase in Src activity, MAPK activation, and eNOS expression. These data suggest that Ang II stimulates Src tyrosine kinase via a pertussis toxin–sensitive pathway, which in turn activates the MAPK pathway, resulting in increased eNOS protein expression in BPAECs.
Abbreviations: angiotensin II, Ang II • bovine pulmonary artery endothelial cells, BPAECs • Dulbecco's modified Eagle's medium, DMEM • dominant negative, DN • epidermal growth factor, EGF • EGF receptor, EGFR • endothelial nitric oxide synthase, eNOS • extracellular-regulated protein kinase, ERK • fluorescein isothiocyanate, FITC • mitogen-activated protein kinase, MAPK • MAPK/ERK kinase, MEK • nitric oxide, NO • neomycin phosphotransferase, NPTII • phosphate-buffered saline, PBS • platelet-derived growth factor receptor, PDGFR • 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-D]pyrimidine, PP2 • protein tyrosine phosphatase, PTP • sodium dodecylsulfate–polyacrylamide gel electrophoresis, SDS-PAGE • vascular smooth muscle cells, VSMCs This article has been cited by other articles:
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