HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 286/2/H570    most recent 00669.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Hynes, S. O. Articles by Katusic, Z. S. Search for Related Content PubMed PubMed Citation Articles by Hynes, S. O. Articles by Katusic, Z. S.

In vivo expression and function of recombinant GTPCH I in the rabbit carotid artery

¹Departments of Anesthesiology, Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905; ²GenVec, Gaithersburg, Maryland 20878; and ³Department of Medicine, National University of Ireland, Galway, Ireland

Submitted 25 July 2003 ; accepted in final form 5 October 2003

Tetrahydrobiopterin (BH4) is an essential co-factor for endothelial nitric oxide synthase enzymatic activity. GTP cyclohydrolase I (GTPCH I) is the rate-limiting enzyme in BH4 synthesis. This study set out to test the hypothesis that in vivo gene transfer of GTPCH I to endothelial cells could increase bioavailability of BH4, enhance biosynthesis of nitric oxide and thereby enhance endothelium-dependent relaxations mediated by nitric oxide. In vivo gene transfer was carried out by adenovirus (Ad)-mediated delivery into rabbit carotid arteries. Each artery was transduced by 20-min intraluminal incubation of 10⁹ plaque-forming units of Ad-encoding GTPCH I (AdGTPCH) or -galactosidase as a control. The rabbits were euthanized 72 h later, and vasomotor function of isolated arteries was assessed by isometric force recording. GTPCH I enzymatic activity, BH4, and oxidized biopterin levels were detected with the use of HPLC, and cGMP was measured with the use of radioimmunoassay. Expression of recombinant proteins was detected predominantly in endothelial cells. Both GTPCH I activity and BH4 levels were increased in arteries transduced with AdGTPCH. However, contraction to phenylephrine (10^–5 to 10^–9 M), endothelium-dependent relaxation to acetylcholine (10^–5 to 10^–9 M) and cGMP levels were not significantly affected by increased expression of GTPCH I. Our results suggest that expression of GTPCH I in vascular endothelium in vivo increases intracellular concentration of BH4. However, under physiological conditions, it appears that this increase does not affect nitric oxide production in endothelial cells of the carotid artery.

nitric oxide synthase; tetrahydrobiopterin; adenovirus

This article has been cited by other articles:

				C.-F. Lam, T. E. Peterson, D. M. Richardson, A. J. Croatt, L. V. d'Uscio, K. A. Nath, and Z. S. Katusic Increased blood flow causes coordinated upregulation of arterial eNOS and biosynthesis of tetrahydrobiopterin Am J Physiol Heart Circ Physiol, February 1, 2006; 290(2): H786 - H793. [Abstract] [Full Text] [PDF]

				O. Suda, L. A. Smith, L. V. d'Uscio, T. E. Peterson, and Z. S. Katusic In Vivo Expression of Recombinant Vascular Endothelial Growth Factor in Rabbit Carotid Artery Increases Production of Superoxide Anion Arterioscler. Thromb. Vasc. Biol., March 1, 2005; 25(3): 506 - 511. [Abstract] [Full Text] [PDF]