Gene transfer with inducible nitric oxide synthase decreases production of urea by arginase in pulmonary arterial endothelial cells.
Nitric oxide (NO) is a vasodilator produced from L-arginine (L-Arg) by NO synthase (NOS). Gene therapy for hypertensive disorders has been proposed using the inducible isoform of NOS (iNOS). L-Arg also can be metabolized to urea and L-ornithine (L-Orn) by arginase, and L-Orn can be metabolized to proline and/or polyamines, which are vital for cellular proliferation. To determine the effect of iNOS gene transfer on arginase, we transfected bovine pulmonary arterial endothelial cells (bPAEC) with an adenoviral vector containing the gene for iNOS (AdiNOS). As expected, NO production in AdiNOS bPAEC was substantially greater than in control bPAEC. Although urea production was significantly less in the AdiNOS bPAEC than in the control bPAEC, despite similar levels of arginase I protein, AdiNOS transfection of bPAEC had no effect on the uptake of L-Arg. Inhibiting NO production with Nomega-nitro-L-arginine methyl ester increased urea production, and inhibiting urea production with L-valine increased nitrite production, in AdiNOS bPAEC. The addition of L-Arg to the medium increased urea production by AdiNOS bPAEC in a concentration-dependent manner. Thus, in these iNOS-transfected bPAEC, the transfected iNOS and native arginase compete for a common intracellular pool of L-Arg. This competition for substrate resulted in impaired proliferation in the AdiNOS-transfected bPAEC. These findings suggest that the use of iNOS gene therapy for pulmonary hypertensive disorders may not only be beneficial through NO-mediated pulmonary vasodilation but also may decrease vascular remodeling by limiting L-Orn production by native arginase.
Stanley
Kate P
KP
Vascular Physiology Group, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM and Center for Developmental Pharmacology and Toxicology, Columbus Children's Research Institute, Columbus, OH 43205, USA.
Chicoine
Louis G
LG
Young
Tamara L
TL
Reber
Kristina M
KM
Lyons
C Richard
CR
Liu
Yusen
Y
Nelin
Leif D
LD
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001119:Arginase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001120:Arginine / Q000494:pharmacology; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D020869:Gene Expression Profiling; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000235:genetics*; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis; D011651:Pulmonary Artery / Q000166:cytology*; D014508:Urea / Q000378:metabolism*
D009569:Nitric Oxide; D014508:Urea; D001120:Arginine; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D001119:Arginase; D019331:NG-Nitroarginine Methyl Ester