title: Nitric oxide reduces vascular smooth muscle cell elastase activity through cGMP-mediated suppression of ERK phosphorylation and AML1B nuclear partitioning.
abstract: Nitric oxide (NO) reduces the severity of pulmonary vascular disease in rats as do elastase inhibitors. We therefore hypothesized that NO inhibits elastase by suppressing mitogen-activated protein kinases that trans-activate AML1B, a transcription factor for elastase. We used cultured pulmonary artery smooth muscle cells in which serum-treated elastin (STE) induces a > threefold increase in elastase activity as evaluated by solubilization of [(3)H]-elastin. NO donors (SNAP and DETA NONOate) inhibited elastase in a dose-dependent manner as did a cGMP mimetic (8-pCPT-cGMP). SNAP inhibition of elastase was reversed by coadministration of a cGMP-PKG inhibitor (Rp-8-pCPT-cGMP). The STE-induced increase in phospho-ERK was suppressed by NO donors and the cGMP mimetic, and reversed by cGMP-PKG inhibitor, as was expression of AML1B and DNA binding in nuclear extracts. A concomitant increase in p38 phosphorylation was also inhibited by SNAP, but whereas MEK inhibitor (PD98059) suppressed elastase and AML1B-DNA binding, a p38 inhibitor (SB202190) did not. Our study uniquely links NO with inhibition of elastase-dependent matrix remodeling in vascular disease by suggesting a cGMP-PKG-related mechanism suppressing ERK-mediated partitioning of AML1B in nuclear extracts.
authors.affiliation: Division of Cardiovascular Research, The Hospital for Sick Children, Department of Laboratory Medicine and Pathobiology, and Medicine, University of Toronto, Toronto, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Mitani
authors.forename: S H
authors.initials: SH
authors.lastname: Zaidi
authors.forename: P
authors.initials: P
authors.lastname: Dufourcq
authors.forename: K
authors.initials: K
authors.lastname: Thompson
authors.forename: M
authors.initials: M
authors.lastname: Rabinovitch
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D050676:Core Binding Factor Alpha 2 Subunit; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D051381:Rats; D013552:Swine; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; C493727:Runx1 protein, rat; D014157:Transcription Factors; D009569:Nitric Oxide; D004247:DNA; D017869:Cyclic GMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D010196:Pancreatic Elastase; D006152:Cyclic GMP