AJP - Heart AJP citation statistics
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


Am J Physiol Heart Circ Physiol 283: H2560-H2566, 2002. First published August 22, 2002; doi:10.1152/ajpheart.00415.2002
0363-6135/02 $5.00
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
283/6/H2560    most recent
00415.2002v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (11)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Eguchi, D.
Right arrow Articles by Katusic, Z. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Eguchi, D.
Right arrow Articles by Katusic, Z. S.
Vol. 283, Issue 6, H2560-H2566, December 2002

Inhibitory effect of recombinant iNOS gene expression on vasomotor function of canine basilar artery

Daihiko Eguchi1, Livius V. d'Uscio1, Chris Wambi1, Deborah Weiler1, Imre Kovesdi2, Timothy O'Brien3, and Zvonimir S. Katusic1

1 Departments of Anesthesiology and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905; 2 Gene Vec, Incorporated, Gaithersburg, Maryland 20878; and 3 Department of Medicine, Clinical Sciences Institute, University College Hospital, Galway, Ireland


    ABSTRACT
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

The present study was designed to determine the effect of recombinant inducible nitric oxide (NO) synthase (iNOS) gene expression on vasomotor function in cerebral arteries. Isolated canine basilar arteries were exposed ex vivo (30 min at 37°C) to an adenoviral vector [107, 108, or 109 plaque-forming units (pfu)/ml] encoding either the iNOS gene or the beta -galactosidase reporter gene. Twenty-four hours after transduction, Western blot analysis demonstrated expression of iNOS protein only in iNOS (109 pfu/ml)-transduced arteries. Immunohistochemical analysis localized iNOS expression predominantly in adventitia. Vascular reactivity of isolated basilar arteries was studied by isometric force recording. Concentration-response curves to UTP (10-9-10-3 M) and diethylaminodiazen-1-ium-1,2-dioate (10-10-10-5 M) were significantly shifted to the right in iNOS gene (109 pfu/ml)-transduced rings compared with control and beta -galactosidase-transduced rings (P < 0.05, n = 5-6). Endothelium-dependent relaxation to bradykinin was significantly attenuated in iNOS-transduced rings (P < 0.001, n = 8). The basal level of cGMP and superoxide anion (O<UP><SUB>2</SUB><SUP>−</SUP></UP>·) production were elevated in iNOS-transduced rings (P < 0.05, n = 7 for cGMP; P < 0.01, n = 6-9 for O<UP><SUB>2</SUB><SUP>−</SUP></UP>· production). Our results suggest that expression of recombinant iNOS in cerebral arteries reduces vasomotor reactivity to both vasoconstrictor and vasodilator agonists. Attenuation of contractions is most likely due to functional antagonism between UTP and cGMP. Reduction of endothelium-dependent relaxation to bradykinin appears to be mediated in part by reduced reactivity of smooth muscle cells to NO.

adventitia; bradykinin; nitric oxide; superoxide anion; inducible nitric oxide synthase


    INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

NITRIC OXIDE (NO) synthesized by enzymatic activity of endothelial NO synthase (eNOS) is a key mediator of smooth muscle relaxation in the normal blood vessels (22). During inflammation, inducible NO synthase (iNOS) is expressed in the vessel wall, including the adventitia (17, 36), and is associated with attenuation of vasoconstriction and vasodilatation (3, 26). A more recent study (8) has demonstrated that ex vivo iNOS gene transfer to normal carotid arteries caused attenuation of vasoconstriction mediated by activation of alpha -adrenergic and thromboxane A2 receptors. Interestingly, in vivo adenovirus-mediated iNOS expression also attenuated endothelium-dependent relaxations (8).

The role of iNOS expression in pathogenesis of vascular diseases is not fully understood. Both beneficial and detrimental effects of iNOS expression on vascular homeostasis have been reported (6, 12, 14, 18, 27). A number of previous studies (13, 32) have demonstrated that vasomotor reactivity of cerebral arteries is different from reactivity of the peripheral arteries. Effects of recombinant iNOS expression on vasomotor function of cerebral arteries have not been studied. Furthermore, iNOS appears to play an important role in pathogenesis of cerebrovascular diseases including stroke (11). Thus the present study was designed to characterize the effect of recombinant iNOS expression in cerebral arteries. We hypothesized that increased expression of iNOS may have inhibitory effect on vasoconstrictor and vasodilator function of cerebral arteries.


    MATERIALS AND METHODS
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

Adenoviral vectors. An E1- and E3-deleted adenoviral vector carrying human iNOS cDNA (AdiNOS) was designed and constructed as previously described (27, 28). An E1- and E3-deleted adenoviral vector carrying the beta -galactosidase (beta -Gal) gene (AdLacZ) was used in all gene transfer experiments as a control, which was designed and constructed as previously described (28, 34). The titer of AdiNOS preparation was ~5 × 1011 plaque-forming units (pfu)/ml, whereas the AdLacZ titer was ~2 × 1012 pfu/ml.

Gene transfer. All procedures were in accordance with the Institutional Animal Care and Use Committee guidelines of Mayo Clinic. Basilar arteries were taken from mongrel dogs (18-27 kg) anesthetized with 30 mg/kg of intravenous Pentothal. To remove blood, arterial rings were gently rinsed with cold (4°C) modified Krebs-Ringer bicarbonate solution [control solution, containing (in mmol/l) 118.3 NaCl, 4.7 KCl, 2.5 CaCl2, 1.2 MgSO4, 1.2 KH2PO4, 25.0 NaHCO3, 0.026 Ca-EDTA, and 11.1 glucose]. Loose perivascular tissue was removed carefully, and arteries were cut in 4-mm-long rings. Rings were randomly assigned for gene transfer and were transduced with adenoviral vectors (107-109 pfu/ml, total volume 300 µl) in minimal essential medium (MEM; containing 0.1% BSA, 100 U/ml penicillin, and 100 µg/ml streptomycin) for 30 min at 37°C. The rings were then transferred to fresh MEM and incubated for 24 h at 37°C in a CO2 incubator (5% CO2, Forma Scientific). The next day, the rings were suspended for isometric force recording in an organ chamber. The viral titer and incubation time were considered to be optimal for ex vivo gene transfer on the basis of results of our previous studies (5, 31). Nontransduced arteries used as controls for certain experiments were incubated in MEM alone for 24 h.

Western blot analysis of recombinant iNOS. Vascular tissues were homogenized in cold lysis buffer [50 mmol/l Tris · HCl (pH 7.5), 0.1 mmol/l EDTA, 0.1 mmol/l EGTA, 0.1% SDS, 0.1% deoxycholate, 1% IGEPAL, and a cocktail of protease inhibitors; all from Sigma]. Total proteins were extracted by rotating the lysate for 1 h at 4°C. The sample was then centrifuged for 5 min at 14,000 g, and the supernatant was harvested. Protein concentrations were determined using an assay kit (Bio-Rad; Hercules, CA). Sample proteins (150 µg/lane) were resolved on a 7.5% SDS-PAGE gel and transferred to nitrocellulose. Positive control was a lysate of mouse macrophages stimulated with interferon-gamma and lipopolysaccharide. Primary antibody was monoclonal anti-iNOS (N39120, BD Transduction; San Diego, CA). Chemiluminescence was used to visualize bands (ECL, Amersham; Arlington Heights, IL).

Immunohistochemical analysis of gene expression. Expression of recombinant iNOS was visualized by immunohistochemistry performed on rings 24 h after transduction. Sections (5 µm) were cut from rings frozen in embedding medium (OCT compound). After tissue was dried onto the slide, it was acetone fixed and endogenous peroxidase blocked in PBS-0.1% sodium azide-0.3% H2O2. Standard methods with slight modifications were used. Blocking of nonspecific proteins was done in 0.5 M PBS with 0.5% Tween 20 and 10% normal rabbit serum. All antibodies were diluted in the same 0.5 PBS-Tween with 1% normal rabbit serum. Primary antibody was a monoclonal anti-iNOS (N39120, 1:50, BD Transduction) followed by a secondary biotinylated rabbit anti-mouse IgG (1:500). Samples were then incubated with peroxidase-conjugated streptavidin. Color was developed with 3-amino-9-ethycarbazole, and tissues were counterstained with hematoxylin. Antibody specificity of staining was confirmed by staining iNOS-transduced sections with an isotype-matched irrelevant antibody or without primary antibody.

Analysis of vascular reactivity. Twenty-four hours after gene transfer, rings were connected to an isometric force-displacement transducer (Grass FT03, Grass Instruments; Quincy, MA) and suspended in an organ chamber filled with 25 ml control solution (37°C, pH 7.4) aerated with 94% O2-6% CO2. Isometric tension was recorded continuously. The rings were allowed to stabilize at a resting tension of 0.2-0.4 g for 1 h. Each ring was then gradually stretched to the optimal point of its length-tension curve (~3.0 g) as determined by the contraction to 10-5 M UTP. All experiments were conducted in the presence of 10-5 M indomethacin to eliminate the possible influence of endogenous cyclooxygenase. The incubation time with indomethacin or NG-nitro-L-arginine methyl ester (L-NAME; 3 × 10-4 M) was 30 or 15 min, respectively. To evaluate relaxation responses, the rings were contracted with median effective concentrations (EC50) of UTP (3 × 10-6-3 × 10-5 M) before the addition of agonists. Concentration-response curves were obtained in a cumulative fashion. Several rings prepared from the same artery were studied in parallel. The relaxations were expressed as a percentage of maximal relaxations induced by 3 × 10-4 M papaverine.

Measurement of cGMP. A radioimmunoassay technique was used to determine the levels of cGMP, as reported previously (31). Rings were initially incubated in MEM in a 5% CO2 incubator at 37°C for 30 min. The rings were then removed from the medium and quickly frozen in liquid nitrogen. After homogenization, cGMP levels were measured by a cGMP radioimmunoassay kit (Amersham). Protein concentration was measured by a DC Protein Assay Kit (Bio-Rad). Rings taken from the same dogs were studied in parallel.

Quantification of vascular O<UP><SUB>2</SUB><SUP>−</SUP></UP>· production. O<UP><SUB>2</SUB><SUP>−</SUP></UP>· production was measured using lucigenin-enhanced chemiluminescence (30). A low concentration of lucigenin (5 µmol/l) was used to avoid the autooxidation of lucigenin (19). Briefly, the basilar artery was cut into 4-mm segments. Rings were placed in a modified Krebs-HEPES buffer (pH 7.4) and equilibrated for 30 min at 37°C. Scintillation vials containing 1 ml Krebs-HEPES buffer with 5 µmol/l lucigenin were placed into a scintillation counter (LS 5000, Beckman Instruments; Fullerton, CA) switched to the out-of-coincidence mode. After dark adaptation, background signals were recorded, and vascular rings were then added to the vial. For 4,5-dihydroxy-1,3-benzenedisulfonic acid (tiron) experiments, iNOS-transduced rings were incubated with tiron (10-2 M) for 20 min before the recording. Photon counts were recorded every 2 min for 8 min, and the background was subtracted. The vessels were then dried for 24 h at 90°C and weighed. The results were expressed as counts per minute per milligram of dry weight.

Drugs. The following pharmacological agents were used: UTP, bradykinin, papaverine hydrochloride, L-NAME, indomethacin, tiron (Sigma), lucigenin (Molecular Probes; Eugene, OR), and diethylaminodiazen-1-ium-1,2-dioate (DEA-NONOate; Cayman Chemical, Ann Arbor, MI). Drugs were dissolved in distilled water. Solutions of DEA-NONOate in the highest concentration were prepared in 1.5 M Tris (pH 8.8). The concentrations of all drugs are expressed as the final moles per liter concentration in the control solution.

Statistical analysis. The results of this study are expressed as means ± SE; n refers to the number of animals. The levels of cGMP and O<UP><SUB>2</SUB><SUP>−</SUP></UP>· in each group were compared by factorial ANOVA. To compare the sensitivity to a vasomotor agent, the half-maximal effective concentrations (EC50) were calculated by nonlinear regression and were expressed as -log M. The concentration-response curves were analyzed by repeated-measures ANOVA followed by Bonferroni-Dunn's post hoc test. Statistical significance was accepted at a P value of <0.05.


    RESULTS
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

Expression and localization of recombinant protein. Expression of recombinant iNOS (109 pfu/ml) protein was confirmed in iNOS-transduced basilar arteries by Western blot analysis. A representative blot is shown in Fig. 1. Immunohistochemistry showed that recombinant iNOS was localized predominantly in the adventitial layer (Fig. 2C). In contrast, control and beta -Gal-transduced vessels did not show iNOS immunoreactivity (Fig. 2, A and B). Incubation of arteries with lower titers of adenovirus (107 and 108 pfu/ml) did not result in detectable expression of recombinant iNOS.


View larger version (17K):
[in this window]
[in a new window]
 
Fig. 1.   Western blot analysis demonstrated significantly increased expression of inducible nitric oxide synthase (iNOS) protein only in adenovirus encoding the iNOS gene (AdiNOS)-transduced basilar arteries [109 plaque-forming units (pfu)/ml]. Positive control, lysate of mouse macrophages stimulated with interferon-gamma and lipopolysaccharide; control, nontransduced arteries; AdLacZ, adenovirus encoding the beta -galactosidase gene.



View larger version (111K):
[in this window]
[in a new window]
 
Fig. 2.   Immunohistochemical staining for recombinant iNOS protein after 24-h AdiNOS transduction (109 pfu/ml). A: control; B: AdLacZ-transduced rings; C: AdiNOS-transduced rings. Positive staining (red-brown) indicates expression and localization of recombinant iNOS. Most recombinant protein was present in the adventitial layer (downward arrowheads). Scale bars, 25 µm; magnification, ×100; L = lumen.

Concentration-dependent contraction to UTP. The concentration-response curve to UTP was significantly shifted to the right in iNOS (109 pfu/ml)-transduced rings (Fig. 3). Maximal contraction to UTP was significantly potentiated in arteries transduced by iNOS (Table 1). Gene transfer with lower titers of iNOS (107 and 108 pfu/ml) did not significantly affect vasomotor reactivity to UTP (Table 1).


View larger version (17K):
[in this window]
[in a new window]
 
Fig. 3.   Concentration-response curves to UTP (10-9-10-3 M) were significantly shifted to the right in AdiNOS-transduced rings compared with control and AdLacZ-transduced rings (P < 0.05, n = 5-6). Data are shown as means ± SE and are expressed as a percentage of the maximal contraction induced by UTP (3 × 10-5 M, 100% = 10.7 ± 1.03, 9.82 ± 0.811, and 12.3 ± 1.11 g for control, AdLacZ-transduced, and AdiNOS-transduced rings, respectively).


                              
View this table:
[in this window]
[in a new window]
 
Table 1.   Contraction to UTP in the isolated canine basilar artery

Endothelium-dependent relaxation to bradykinin. During contraction to UTP (3 × 10-6-3 × 10-5 M), bradykinin (10-10-10-6 M) caused endothelium-dependent relaxations. L-NAME (3 × 10-4 M) abolished relaxations to bradykinin (data not shown), suggesting that the effect of bradykinin was exclusively mediated by NO. The relaxations to bradykinin in iNOS (109 pfu/ml)-transduced vessels were significantly inhibited compared with control and beta -Gal-transduced rings (Fig. 4). Gene transfer with lower titers of iNOS (107 and 108 pfu/ml) did not significantly affect relaxations to bradykinin (Table 2). Twenty-four hours of incubation with a 10-2 M concentration of tiron did not improve impaired endothelium-dependent relaxations to bradykinin in iNOS-transduced arteries (33 ± 5% and 7 ± 15%, relaxation to 10-6 bradykinin in iNOS and iNOS plus tiron arteries, respectively). Tiron did not affect relaxations to bradykinin in control and beta -Gal-transduced arteries (71 ± 8% and 68 ± 12%, relaxation to 10-6 M bradykinin for beta -Gal and beta -Gal plus tiron arteries, respectively; n = 3 dogs).


View larger version (20K):
[in this window]
[in a new window]
 
Fig. 4.   Endothelium-dependent relaxation to bradykinin was significantly impaired in arteries expressing iNOS (maximum relaxation = 66.6 ± 5.85% and 30.3 ± 9.45% in AdLacZ- and AdiNOS-transduced rings, respectively; P < 0.01, n = 8). Data are shown as means ± SE and are expressed as a percentage of the maximal relaxation induced by papaverine (3 × 10-4 M, 100% = 4.05 ± 0.508, 4.19 ± 0.498, and 3.18 ± 0.411 g for control, AdLacZ-transduced, and AdiNOS-transduced rings, respectively).


                              
View this table:
[in this window]
[in a new window]
 
Table 2.   Endothelium-dependent relaxation to bradykinin in the isolated canine basilar artery

Endothelium-independent relaxation to DEA-NONOate. During contractions to UTP (3 × 10-6-3 × 10-5 M), DEA-NONOate (10-10-10-5 M) caused concentration-dependent relaxations. The concentration-response curve to DEA-NONOate was significantly shifted to the right in iNOS (109 pfu/ml)-transduced rings (Fig. 5). Gene transfer with lower titers of iNOS (107 and 108 pfu/ml) did not significantly affect relaxations to DEA-NONOate (Table 3).


View larger version (16K):
[in this window]
[in a new window]
 
Fig. 5.   The concentration-response curve to diethylaminodiazen-1-ium-1,2-dioate (DEA-NONOate; 10-10-10-5 M) was significantly shifted to the right in AdiNOS-transduced rings compared with control and AdLacZ-transduced rings (n = 6, P < 0.05). Data are shown as means ± SE and are expressed as a percentage of the maximal relaxation induced by papaverine (3 × 10-4 M, 100% = 4.29 ± 0.684, 4.48 ± 0.286, and 3.63 ± 0.639 g for control, AdLacZ-transduced, and AdiNOS-transduced rings, respectively).


                              
View this table:
[in this window]
[in a new window]
 
Table 3.   Endothelium-independent relaxation to DEA-NONOate

Basal cGMP production. Basal production of cGMP was significantly increased in iNOS (109 pfu/ml)-transduced rings compared with control and beta -Gal-transduced rings (Fig. 6; P < 0.05, n = 7).


View larger version (14K):
[in this window]
[in a new window]
 
Fig. 6.   The basal levels of cGMP production. Columns and bars represent means ± SE. Transduction with AdiNOS significantly increased the basal level of cGMP compared with control and AdLacZ-transduced arteries (*P < 0.05, n = 7).

O<UP><SUB>2</SUB><SUP>−</SUP></UP>· production. Lucigenin-enhanced chemiluminescence showed a three- to fourfold higher basal O<UP><SUB>2</SUB><SUP>−</SUP></UP>· level in AdiNOS (109 pfu/ml)-transduced rings compared with levels in control and AdLacZ-transduced rings (Fig. 7; P < 0.05, n = 4-9). Increased production of O<UP><SUB>2</SUB><SUP>−</SUP></UP>· was inhibited in the presence of the O<UP><SUB>2</SUB><SUP>−</SUP></UP>· scavenger tiron (10-2 M).


View larger version (14K):
[in this window]
[in a new window]
 
Fig. 7.   Expression of recombinant iNOS significantly increased formation of O<UP><SUB>2</SUB><SUP>−</SUP></UP>· (*P < 0.01, n = 6-9). Incubation with tiron (10-2 M for 20 min) abolished the O<UP><SUB>2</SUB><SUP>−</SUP></UP>· production.


    DISCUSSION
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

This is the first study to examine the effect of recombinant iNOS on vasomotor function of cerebral arteries. After ex vivo gene transfer, morphological analysis indicated that iNOS was mostly expressed in adventitia. Expression of recombinant iNOS in canine cerebral arteries reduced contractions to UTP and attenuated relaxations to endogenous NO released from the endothelium as well as exogenous NO generated by DEA-NONOate. We also demonstrated that iNOS caused a significant increase in cGMP levels and superoxide anion production in transduced cerebral arteries.

Immunohistochemistry and Western blot analysis were employed to confirm expression and determine localization of recombinant iNOS. As in our previous ex vivo studies, expression of recombinant iNOS was mainly localized in adventitia (5, 25, 31). Immunogold labeling and electron microscopy studies demonstrated that adventitial fibroblasts are very good target cells for expression of recombinant proteins (5, 31). Under physiological conditions, the adventitia stabilizes the vascular wall and serves to connect the blood vessel to surrounding tissue. However, in diseased arteries, adventitia can play an important role in pathogenesis of vascular dysfunction (9, 15). It is interesting that cerebral arteries do not have an external elastic lamina that separates adventitia from the smooth muscle cells. This morphological feature may enable NO released from fibroblasts to travel even longer distances within the media of cerebral arteries.

The most striking finding of the present study is that both vasoconstrictor and vasodilator responses are blunted in arteries expressing recombinant iNOS in adventitia. The inhibitory effect of iNOS expression on vasoconstrictor effect is not surprising, and our findings are consistent with reported ability of recombinant iNOS to inhibit the contractile effects of phenylephrine and U-46619 (8). This finding is best explained by the increase in cGMP content in the AdiNOS-transduced vascular wall. cGMP is a well-established second messenger and mediator of vasodilator effect of NO (23), and high cGMP levels are to be expected in arteries transduced by iNOS (16). Indeed, in our previous study (1), we reported an ~10-fold increase in cGMP levels in canine basilar arteries transduced with AdeNOS and treated with the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). It should be noted that, in the present study, cGMP was measured in the absence of IBMX, and this may explain the only threefold increase of cGMP detected in AdiNOS-transduced arteries. It is interesting that the absolute value of the maximal contraction to UTP was significantly augmented in iNOS-transduced arteries. At the present time, we do not have an explanation for this observation.

High NO levels produced by iNOS may also provide an explanation for the reduced reactivity of smooth muscle cells to endogenous and exogenous NO. Our results are in agreement with those obtained using eNOS transgenic mice and iNOS gene transfer in the rabbit carotid artery (8, 24). In both studies, chronic high production of NO in the arterial wall was associated with a reduced vasodilator effect of NO. It appears that the vascular system can adapt to a high local concentration of NO by downregulating the signal transduction mechanism responsible for mediation of NO-induced vasodilatation. The exact molecular mechanism underlying this adaptation after iNOS gene transfer remains to be clarified.

Besides high basal levels of cGMP in iNOS-transduced arteries, increased production of superoxide anions may provide an additional explanation for attenuation of endothelium-dependent relaxation mediated by NO and relaxation to DEA-NONOate. Inconsistent findings were reported in a previous attempt to normalize the vasomotor function of the iNOS-transduced carotid artery with superoxide dismutase (8). This is most likely due to the fact that superoxide anion reacts with NO more rapidly than with superoxide dismutase (4). Chemical antagonism between NO and superoxide is source of a potent oxidant, peroxynitrite, which can cause nitration of proteins, leading to irreversible alteration in function (2). We have also been unable to normalize the vasomotor function of iNOS-transduced arteries by a superoxide anion scavenger, tiron.

The exact source of superoxide anions in AdiNOS-transduced arteries is unknown. However, previous biochemical and pharmacological studies demonstrated that NOS itself could be a potent source of superoxide anions (35). iNOS generates superoxide anions from the reductase domain. This is in contrast to the neuronal and endothelial isoforms of NOS, which generate superoxide mostly from the oxigenase domain (21). Furthermore, iNOS-induced formation of superoxide anions occurs even in the presence of a high concentration of substrate, L-arginine (1 mM), whereas L-arginine can suppress production of superoxide anions by neuronal NOS or eNOS (35). A recent study by Huisman and colleagues demonstrated that the oxigenase domain of iNOS may also be a source of superoxide anion (10). Supplementation with a cofactor, tetrahydrobiopterin, reduced superoxide anion formation by iNOS, suggesting that suboptimal concentration of tetrahydrobiopterin may contribute to the iNOS-mediated production of superoxide anion (10). We did not measure tetrahydrobiopterin levels in arteries expressing recombinant iNOS, and further studies are needed to determine whether this mechanism may explain increased superoxide production in iNOS-transduced arteries.

A major limitation of the present study is that the exclusive expression of iNOS by adenovirus-mediated gene transfer in normal arteries is not associated with coexpression of coordinately regulated vascular genes (20). Proinflammatory stimuli can upregulate expression of many proteins that are important for iNOS enzymatic activity or vascular effects of NO, including the L-arginine transporter and GTP cyclohydrolase I, the rate-limiting enzyme in biosynthesis of tetrahydrobiopterin (29). It is interesting that ongoing phase I gene therapy clinical trials with iNOS have been designed to prevent coronary artery restenosis and occlusion of arterial-venous fistula (33). In both applications, inhibition of smooth muscle cells proliferation and vascular remodeling (rather than normalization of vasomotor function) of diseased blood vessels are the major therapeutic goals. Obviously, a better understanding of the natural course of endogenous iNOS expression and its function in the diseased vascular wall may help to optimize current applications and develop new therapeutic indications of recombinant iNOS. Whether under certain circumstances iNOS gene transfer may be used in the prevention and treatment of cerebrovascular diseases remains to be determined.

Ex vivo gene transfer of iNOS to cerebral arteries results in expression of functional protein, mostly in adventitia. Increased production of cGMP and superoxide anions in iNOS-transduced arteries may explain the attenuation of vasomotor function. Whether these effects of recombinant iNOS may be beneficial (or detrimental) in the prevention and treatment of cerebrovascular diseases requires further improvement in understanding of iNOS vascular biology.


    ACKNOWLEDGEMENTS

We thank Leslie Smith for technical assistance and Janet Beckman for preparing the manuscript.


    FOOTNOTES

This work was supported in part by National Institutes of Health Grants HL-53524, HL-58080, HL-066958, and NS-37491, the American Heart Association Bugher Award for the Investigation of Stroke, and the Mayo Foundation. L. d'Uscio was the recipient of a stipend from the Swiss National Science Foundation and the American Heart Association, Northland Affiliate.

Address for reprint requests and other correspondence: Z. S. Katusic, Dept. of Anesthesiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905 (E-mail: katusic.zvonimir{at}mayo.edu).

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

August 22, 2002;10.1152/ajpheart.00415.2002

Received 28 May 2002; accepted in final form 19 August 2002.


    REFERENCES
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

1.   Akiyama, M, Eguchi D, Weiler D, O'Brien T, Kovesdi I, Scotland RS, Sessa WC, and Katusic ZS. Expression and function of recombinant S.1179D endothelial nitric oxide synthase in canine cerebral arteries. Stroke 33: 1071-1076, 2002[Abstract/Free Full Text].

2.   Aulak, KS, Miyagi M, Yan L, West KA, Massillon D, Crabb JW, and Stuehr DJ. Proteomic method identifies proteins nitrated in vivo during inflammatory challenge. Proc Natl Acad Sci USA 98: 12056-12061, 2001[Abstract/Free Full Text].

3.   Beasley, D, Cohen RA, and Levinsky NG. Endotoxin inhibits contraction of vascular smooth muscle in vitro. Am J Physiol Heart Circ Physiol 258: H1187-H1192, 1990[Abstract/Free Full Text].

4.   Beckman, JS, and Koppenol WH. Nitric oxide, superoxide and peroxynitrate: the good, the bad, and the ugly. Am J Physiol Cell Physiol 271: C1424-C1437, 1996[Abstract/Free Full Text].

5.   Chen, AF, O'Brien T, Tsutsui M, Kinoshita H, Pompili VJ, Crotty TB, Spector DJ, and Katusic ZS. Expression and function of recombinant endothelial nitric oxide synthase gene in canine basilar artery. Circ Res 80: 327-335, 1997[Abstract/Free Full Text].

6.   Detmers, PA, Hernandez M, Mudgett J, Hassing H, Burton C, Mundt S, Chun S, Fletcher D, Card DJ, Lisnock J, Weikel R, Bergstrom JD, Shevell DE, Hermanowski-Vosatka A, Sparrow CP, Chao YS, Rader DJ, Wright SD, and Pure E. Deficiency in inducible nitric oxide synthase results in reduced atherosclerosis in apolipoprotein E-deficient mice. J Immunol 165: 3430-3435, 2000[Abstract/Free Full Text].

7.   Gunnett, CA, Chu Y, Heistad DD, Loihl A, and Faraci FM. Vascular effects of LPS in mice deficient in expression of the gene for inducible nitric oxide synthase. Am J Physiol Heart Circ Physiol 275: H416-H421, 1998[Abstract/Free Full Text].

8.   Gunnett, CA, Lund DD, Chu Y, Brooks RMII, Faraci FM, and Heistad DD. NO-dependent vasorelaxation is impaired after gene transfer of inducible NO-synthase. Arterioscler Thromb Vasc Biol 21: 1281-1287, 2001[Abstract/Free Full Text].

9.   Gutterman, DD. Adventitia-dependent influences on vascular function. Am J Physiol Heart Circ Physiol 277: H1265-H1272, 1999[Free Full Text].

10.   Huisman, A, Vos I, Van Faassen EE, Joles JA, Grone HJ, Martasek P, Van Zonneveld AJ, Vanin AF, and Rabelink TJ. Anti-inflammatory effects of tetrahydrobiopterin on early rejection in renal allografts: modulation of inducible nitric oxide synthase. FASEB J 16: 1135-1137, 2002[Abstract/Free Full Text].

11.   Iadecola, C, Zhang F, Casey R, Clark HB, and Ross ME. Inducible nitric oxide synthase gene expression in vascular cells after transient focal cerebral ischemia. Stroke 27: 1373-1380, 1996[Abstract/Free Full Text].

12.   Ishigami, M, Swertfeger DK, Hui MS, Granholm NA, and Hui DY. Apolipoprotein E inhibition of vascular smooth muscle cell proliferation but not the inhibition of migration is mediated through activation of inducible nitric oxide synthase. Arterioscler Thromb Vasc Biol 20: 1020-1026, 2001[Abstract/Free Full Text].

13.   Katusic, ZS, and Shepherd JT. Endothelium-derived vasoactive factors: II. Endothelium-dependent contraction. Hypertension 18: III86-III92, 1991[Medline].

14.   Kessler, P, Bauersachs J, Busse R, and Schini-Kerth VB. Inhibition of inducible nitric oxide synthase restores endothelium-dependent relaxations in proinflammatory mediator-induced blood vessels. Arterioscler Thromb Vasc Biol 17: 1746-1755, 1997[Abstract/Free Full Text].

15.   Khurana, VG, and Katusic ZS. Gene transfer for cerebrovascular disease. Curr Cardiol Rep 3: 10-16, 2001[Medline].

16.   Kleinert, H, Boissel JP, Schwarz PM, and Förstermann U. Regulation of the expression of nitric oxide synthase isoforms. In: Nitric Oxide. Biology and Pathobiology, edited by Ignarro LJ.. San Diego, CA: Academic, 2000, p. 105-128.

17.   Kleschyov, AL, Muller B, Keravis T, Stoeckel ME, and Stoclet JC. Adventitia-derived nitric oxide in rat aortas exposed to endotoxin: cell origin and functional consequences. Am J Physiol Heart Circ Physiol 279: H2743-H2751, 2000[Abstract/Free Full Text].

18.   Kuhlencordt, PJ, Chen J, Han F, Astern J, and Huang PL. Genetic deficiency of inducible nitric oxide synthase reduces atherosclerosis and lowers plasma lipid peroxides in apolipoprotein E-knockout mice. Circulation 103: 3099-3104, 2001[Abstract/Free Full Text].

19.   Li, Y, Zhu H, Kuppusamy P, Roubaud V, Zweier JL, and Trush MA. Validation of lucigenin (bis-N-methylacridinium) as a chemilumigenic probe for detecting superoxide anion radical production by enzymatic and cellular systems. J Biol Chem 273: 2015-2023, 1998[Abstract/Free Full Text].

20.   Loscalzo, J. Inducible NO synthesis in the vasculature. Molecular context defines physiological response. Arterioscler Thromb Vasc Biol 21: 1259-1260, 2001[Free Full Text].

21.   Masters, BS. Structural variations to accommodate functional themes of the isoforms of NO synthases. In: Nitric Oxide. Biology and Pathobiology, edited by Ignarro LJ.. San Diego, CA: Academic, 2000, p. 91-106.

22.   Moncada, S, and Higgs A. The L-arginine-nitric oxide pathway. N Engl J Med 329: 2002-2012, 1993[Free Full Text].

23.   Murad, F. Regulation of cytosolic guanylyl cyclase by nitric oxide: the NO-cyclic GMP signal transduction system. In: Cyclic GMP. Synthesis, Metabolism, and Function, edited by Murad F.. San Diego, CA: Academic, 1994, p. 10-33.

24.   Ohashi, Y, Kawashima S, Hirata K, Yamashita T, Ishida T, Inoue N, Sakoda T, Kurihara H, Yazaki Y, and Yokoyama M. Hypotension and reduced nitric oxide-elicited vasorelaxation in transgenic mice overexpressing endothelial nitric oxide synthase. J Clin Invest 102: 2061-2071, 1998[Web of Science][Medline].

25.   Onoue, H, Tsutsui M, Smith L, Stelter A, O'Brien T, and Katusic ZS. Expression and function of recombinant endothelial nitric oxide synthase gene in canine basilar artery after experimental subarachnoid hemorrhage. Stroke 29: 1959-1965, 1998[Abstract/Free Full Text].

26.   Parker, JL, and Adams HR. Selective inhibition of endothelium-dependent vasodilator capacity by Escherichia coli endotoxemia. Circ Res 72: 539-551, 1993[Abstract/Free Full Text].

27.   Shears, LL, Kawaharada N, Tzeng E, Billiar TR, Watkins SC, Kovesdi I, Lizonova A, and Pham SM. Inducible nitric oxide synthase suppresses the development of allograft arteriosclerosis. J Clin Invest 100: 2035-2042, 1997[Web of Science][Medline].

28.   Shears, LL, Kibbe MR, Murdock AD, Billiar TR, Lizonova A, Kovesdi I, Watkins SC, and Tzeng E. Efficient inhibition of intimal hyperplasia by adenovirus-mediated inducible nitric oxide synthase gene transfer to rats and pigs in vivo. J Am Coll Surg 187: 295-306, 1998[Web of Science][Medline].

29.   Simmons, WW, Ungureanu-Longrois D, Smith GK, Smith TW, and Kelly RA. Glucocorticoids regulate inducible nitric oxide synthase by inhibiting tetrahydrobiopterin synthesis and L-arginine transport. J Biol Chem 271: 23928-23937, 1996[Abstract/Free Full Text].

30.   Skatchkov, MP, Sperling D, Hink U, Mulsch A, Harrison DG, Sindermann I, Meinertz T, and Münzel T. Validation of lucigenin as a chemiluminescent probe to monitor vascular superoxide as well as basal vascular nitric oxide production. Biochem Biophys Res Commun 254: 319-324, 1999[Web of Science][Medline].

31.   Tsutsui, M, Chen AF, O'Brien T, Crotty TB, and Katusic ZS. Adventitial expression of recombinant eNOS gene restores NO production in arteries without endothelium. Arterioscler Thromb Vasc Biol 18: 1231-1241, 1998[Abstract/Free Full Text].

32.   Vanhoutte, PM, Katusic ZS, and Shepherd JT. Vasopressin induces endothelium-dependent relaxations of cerebral and coronary, but not of systemic arteries. Hypertension 2: S421, 1984.

33.   Von der Leyen, HE, and Dzau VJ. Therapeutic potential of nitric oxide synthase gene manipulation. Circulation 103: 2760-2765, 2001[Free Full Text].

34.   Wickham, TJ, Tzeng E, Shears LL, II, Roelvink PW, Li Y, Lee GM, Brough DE, Lizonova A, and Kovesdi I. Increased in vitro and in vivo gene transfer by adenovirus vectors containing chimeric fiber proteins. J Virol 71: 8221-8229, 1997[Abstract].

35.   Xia, Y, Roman LJ, Masters BSS, and Zweier JL. Inducible nitric-oxide synthase generates superoxide from the reductase domain. J Biol Chem 273: 22635-22639, 1998[Abstract/Free Full Text].

36.   Zhang, H, Du Y, Cohen RA, Chobanian AV, and Brecher P. Adventitia as a source of inducible nitric oxide synthase in the rat aorta. Am J Hypertens 12: 467-475, 1999[Web of Science][Medline].


Am J Physiol Heart Circ Physiol 283(6):H2560-H2566
0363-6135/02 $5.00 Copyright © 2002 the American Physiological Society



This article has been cited by other articles:


Home page
StrokeHome page
J. Kitayama, F. M. Faraci, C. A. Gunnett, and D. D. Heistad
Impairment of Dilator Responses of Cerebral Arterioles During Diabetes Mellitus: Role of Inducible NO Synthase
Stroke, August 1, 2006; 37(8): 2129 - 2133.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Heart Circ. Physiol.Home page
C. A. Gunnett, D. D. Lund, F. M. Faraci, and D. D. Heistad
Vascular interleukin-10 protects against LPS-induced vasomotor dysfunction
Am J Physiol Heart Circ Physiol, August 1, 2005; 289(2): H624 - H630.
[Abstract] [Full Text] [PDF]


Home page
Arterioscler. Thromb. Vasc. Bio.Home page
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]


Home page
StrokeHome page
J. Sorenson, A. V. R. Santhanam, L. A. Smith, M. Akiyama, W. C. Sessa, and Z. S. Katusic
Expression and Function of Recombinant S1179D Endothelial NO Synthase in Human Pial Arteries
Stroke, January 1, 2005; 36(1): 158 - 160.
[Abstract] [Full Text] [PDF]


Home page
J. Appl. Physiol.Home page
L. G. Chicoine, E. Tzeng, R. Bryan, S. Saenz, M. L. Paffett, J. Jones, C. R. Lyons, T. C. Resta, L. D. Nelin, and B. R. Walker
Intratracheal adenoviral-mediated delivery of iNOS decreases pulmonary vasoconstrictor responses in rats
J Appl Physiol, November 1, 2004; 97(5): 1814 - 1822.
[Abstract] [Full Text] [PDF]


Home page
Arterioscler. Thromb. Vasc. Bio.Home page
Z. S. Katusic, N. M. Caplice, and K. A. Nath
Nitric Oxide Synthase Gene Transfer as a Tool to Study Biology of Endothelial Cells
Arterioscler Thromb Vasc Biol, November 1, 2003; 23(11): 1990 - 1994.
[Abstract] [Full Text] [PDF]


This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
283/6/H2560    most recent
00415.2002v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (11)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Eguchi, D.
Right arrow Articles by Katusic, Z. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Eguchi, D.
Right arrow Articles by Katusic, Z. S.


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online