© 2000 American Heart Association, Inc.
Integrative Physiology |
Prevention of Hypoxia-Induced Pulmonary Hypertension by Enhancement of Endogenous Heme Oxygenase-1 in the Rat
From the Division of Newborn Medicine, Department of Pediatrics (H.C., T.M., H.K., S.K.), Children’s Hospital, Harvard Medical School, and Cardiovascular Biology Laboratory, Pulmonary and Critical Care Division (C.-M.H., B.A., M.A.P.), Brigham and Women’s Hospital, Harvard School of Public Health, Boston, Mass.
Correspondence to Stella Kourembanas, MD, Children’s Hospital, 300 Longwood Ave, Enders 9, Boston, MA 02115. E-mail kourembanas{at}hub.tch.harvard.edu
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Abstract |
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Abstract—We investigated the role of heme oxygenase (HO)–1 in the development of hypoxia-induced pulmonary hypertension. HO catalyzes the breakdown of heme to the antioxidant bilirubin and the vasodilator carbon monoxide. Hypoxia is a potent but transient inducer of HO-1 in vascular smooth muscle cells in vitro and in the lung in vivo. By using agonists of HO-1, we sustained a high expression of HO-1 in the lungs of rats for 1 week. We report that this in vivo enhancement of HO-1 in the lung prevented the development of hypoxic pulmonary hypertension and inhibited the structural remodeling of the pulmonary vessels. The mechanism(s) underlying this effect may involve a direct vasodilating and antiproliferative action of endogenous carbon monoxide, as well as an indirect effect of carbon monoxide on the production of vasoconstrictors. These results provide evidence that enhancement of endogenous adaptive responses may be used to prevent hypoxia-induced pulmonary hypertension.
Key Words: vascular remodeling • gene expression • hypoxia
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Heme oxygenase (HO) is the rate-limiting enzyme in the degradation of heme to biliverdin and subsequently to bilirubin. The reaction catalyzed by HO is the major source of carbon monoxide (CO) in the body, which is increasingly recognized as a physiologically important molecule rather than a toxic waste product.1 There are 3 known isoforms of HO. HO-1 is inducible,2 whereas HO-2 and HO-3 are constitutively expressed.3 4 HO-3 is highly homologous to HO-2 but has not been characterized fully. HO-2 is the predominant form expressed in the central nervous system, where CO is thought to act as a neurotransmitter via the soluble guanylate cyclase/cGMP pathway.5 HO-1, the inducible form of the enzyme, is highly expressed in erythropoietic tissues, where its function is heme degradation, but it is also expressed in vascular smooth muscle cells (SMCs),6 where its role may include regulation of vascular tone. Several lines of investigation provide evidence that CO may be a physiological regulator of cellular interactions in the vasculature, acting as a direct and indirect vasodilator; directly, CO acts via activation of soluble guanylate cyclase and elevation of cGMP, as in rat aortic and coronary vascular SMC preparations6 7 as well as in dog femoral, carotid, and coronary arteries.8 Indirectly, SMC-derived CO may cause SMC relaxation by inhibiting the hypoxic induction of the vasoconstrictors endothelin-1 (ET-1) and platelet-derived growth factor-B (PDGF-B) in adjacent endothelial cells.9 In addition to its vasodilatory actions, CO was shown to inhibit SMC proliferation by regulating the cell cycle–specific transcription factor E2F-1,10 as well as the expression of the mitogens ET-1 and PDGF-BB in culture.9
A variety of cellular stressors, such as heat shock, oxidative stress, heavy metals, and hemoproteins, induce HO-1.11 12 13 Therefore, a protective/antioxidant role has been proposed for HO-1, as well as its enzymatic product, bilirubin.14 We found that SMC HO-1 is also induced by hypoxia in vitro in a time-dependent fashion with an initial 6-fold induction of mRNA at 12 hours of exposure followed by return to baseline by 48 hours of continued hypoxic exposure. This induction is accompanied by increased HO-1 activity and cGMP concentrations in vitro.6 In the rat model of chronic hypoxia, there is a sustained induction of vasoconstrictors such as ET-115 and angiotensin II,16 and although increased production of the vasodilator nitric oxide has been reported,17 18 the net balance of these agents favors active vasoconstriction and wall remodeling. We speculated that HO-1 may be transiently induced by hypoxia in the lung, representing an endogenous adaptive response and that because of its transient nature, this response is ineffective in counteracting the actions of other mediators that are persistently induced under hypoxic conditions. We thus hypothesized that sustained induction of HO-1 in the setting of hypoxia may alter this balance and prevent or ameliorate the development of pulmonary hypertension. We report here that treatment of rats with the HO-1 inducers NiCl2 and hemin caused a sustained increased expression of HO-1 in the lung and inhibited the development of structural remodeling and pulmonary hypertension by chronic hypoxia.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Hypoxic Exposure and Treatment With NiCl2 or Hemin
Adult virus-free male Sprague-Dawley rats weighing 350 to 375 g were instrumented (Zivic Miller) and transported to our animal care facility with right ventricular and aortic catheters in place. They were then exposed to normobaric hypoxia (10% oxygen environment) in a ventilated Plexiglas box for 1 week. Age- and weight-matched control rats were maintained in 21% oxygen in the same virus-free room. Four to eight animals were studied in each group. To establish the hypoxic conditions, the chamber was flushed with a gas mixture of room air and nitrogen from a liquid nitrogen reservoir as previously described.19 The chamber was opened every 2 days for 30 minutes to clean the cages, replenish food, and water and flush right ventricular and aortic catheters. The NiCl2-treated animals were given subcutaneous injections of 250 mmol/kg of NiCl2 in normal saline every 48 hours, whereas the control animals were injected with the same volume of saline alone. These doses were chosen after preliminary studies showed that they were effective in inducing HO-1 (data not shown). The hemin-treated animals were given intraperitoneal injections of 15 mg/kg of hemin in DMSO every 48 hours. The animals were subsequently subjected to hemodynamic measurements and then euthanized with intraperitoneal pentobarbital (75 mg/kg). Their lungs were harvested for Northern and Western analyses and histological studies. As we previously described,19 the left mainstem bronchus was ligated and the left lung was excised, flash-frozen in liquid nitrogen, and stored at -80°C until RNA or protein extraction. The pulmonary artery was infused with normal saline to clear the blood from the pulmonary vessels. For histological analysis, the pulmonary veins were subsequently ligated, and the pulmonary artery and trachea were perfused with 4% paraformaldehyde at constant pressure (100 cm H2O for the pulmonary artery and 25 cm H2O for the trachea) to fully distend the pulmonary blood vessels and airway, respectively. Peripheral lung specimens were then excised, fixed in 4% paraformaldehyde, paraffin-embedded, and sectioned for morphometric analysis of pulmonary arterioles. All animal experiments were performed in accordance with National Institutes of Health (NIH) guidelines and were approved by the institutional standing committee on animals.
Northern Analysis
Total lung RNA was isolated by guanidinium isothiocyanate
extraction as previously reported,20 fractionated by
formaldehyde gel electrophoresis, and transferred onto Duralose UV
membranes (Stratagene). Fifteen micrograms of total RNA was loaded in
each lane. The filters were hybridized with HO-1 and ET-1 cDNA probes
specific for the rat HO-1 gene6 and the rat ET-1
gene.9 The mouse ß-actin gene21 was used
for normalization of RNA loading. Hybridization and washes were
performed using standard conditions.19 For quantification,
the autoradiographs were scanned using a Phosphor Imager
analyzer (Molecular Dynamics).
Western Analysis
Frozen lung tissue was homogenized in lysis buffer
(containing, in mmol/L, NaCl 150, Tris [pH 7.5] 30, and PMSF 1;
0.25 mol/L sucrose; 5 µg/mL leupeptin; and 1.9 µg/mL aprotinin),
and protein concentrations were determined with a dye-binding assay
(Bio-Rad) using BSA as standard. Fifty micrograms of total lung protein
were prepared in sample buffer and boiled at 95°C for 5 minutes.
Samples were subjected to electrophoresis in a 12% SDS
polyacrylamide gel for 1 hour at 25 mA. The gel was transferred
electrophoretically onto polyvinylidene difluoride membranes
(Millipore Corp), and Western blotting was performed using primary
rabbit polyclonal antibody against rat HO-1 (1:1000 dilution) purchased
from StressGen. For detection of signal, we used an enhanced
chemiluminescence detection kit from Amersham, and for quantification,
we used Fotolook and NIH Image Software programs.
Hemodynamic Measurements
Hemodynamic measurements were performed at the
end of the experimental period of 1 week in conscious rats.
Systolic and mean right ventricular pressure (RVP)
and mean arterial blood pressure (MAP) were continuously
recorded for 2 minutes using MacLab monitoring equipment from CB
Sciences, Inc. Results are reported in mm Hg. The position of the
catheters was confirmed after the animals were euthanized.
Morphometric Analysis
Six-micrometer lung sections were stained with
hematoxylin and eosin and examined with light microscopy. At least 5
representative pulmonary arterioles chosen from
3 different sections from each animal were independently examined by 2
of the investigators (H.C. and B.A.), who were not aware of the origin
of the lung sections. The images of the arterioles were captured and
analyzed using NIH Image software.22 Blood vessels
were identified according to the accompanying airway, and intra-acinar
vessels were chosen. Percentage medial thickness was determined by
dividing the area occupied by the medial muscular layer by the total
cross-sectional area of the arteriole. This method was used to account
for uneven medial thickness and areas that had obliquely sectioned
pulmonary arterioles.
Measurement of Circulating cGMP Concentrations
Blood specimens were collected in EDTA tubes and
centrifuged, and plasma was separated and stored at –80°C
until assayed. Amprep SAX minicolumns were used to extract cGMP from
plasma samples, and plasma cGMP concentrations were measured in a
single batch by radioimmunoassay (Amersham) as previously
described.23 The sensitivity of the assay was 0.5
fmol/tube, and the antibody cross-reacted fully with cGMP and <0.001%
with other adenosine or guanosine phosphates. Intra-assay
coefficient of variation was 5%. cGMP concentrations are expressed as
pmol/L.
Statistical Methods
The nonparametric ANOVA (Kruskal-Wallis) test and
Dunn multiple-comparisons tests were used to compare median values
among groups, respectively, and differences were considered significant
if P<0.05.
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Results |
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In Vivo Induction of HO-1 mRNA and Protein in the Lung
We first examined whether hypoxia regulates HO-1 expression in vivo as it does in vitro. Similar to our in vitro observations in cultured SMCs,6 lung HO-1 mRNA was transiently induced by hypoxia in vivo but to a much lesser degree (2- to 3-fold in total lung versus 7-fold induction in cultured SMCs). After exposure of rats to hypoxia, we found that lung HO-1 mRNA levels increased 2- to 3-fold at 9 hours of hypoxia and returned to almost basal levels by 48 hours of hypoxic exposure (Figure 1A
). In preliminary experiments,
we used a number of known HO-1 agonists24 25 26 at various
concentrations to assess their effectiveness in inducing and sustaining
high levels of HO-1 mRNA in the lung in vivo. After treatment of
animals with NiCl2 (250 mmol/kg every 48
hours) or hemin (15 mg/kg every 48 hours), we found a mild induction of
HO-1 mRNA in the lung after 48 hours (1.4- to 2.3-fold; data not
shown). We found a more marked increase (average of 3-fold above
baseline) after 1 week of treatment with these inducers under
hypoxia (Figure 1B). This correlated with a 4- to 5-fold
induction of HO-1 protein levels in the lungs of hypoxic animals
treated with NiCl2 or hemin compared with the
normoxic controls (Figure 1C). As expected, HO-1 protein levels
in the lung had returned to baseline after 1 week of hypoxic exposure
in the absence of NiCl2 or hemin treatment
(Figure 1C).
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Prevention of Hypoxia-Induced Pulmonary
Hypertension
We measured RVP as an indicator of pulmonary artery
pressure in conscious rats. Systolic RVP in normoxic rats was
7.5±2.1 mm Hg (mean±SEM, n=5) (Figure 2A). As expected, the hypoxic animals
developed pulmonary hypertension after 1 week of exposure to
10% oxygen. Their systolic RVP was 39.7±9.8 mm Hg
(mean±SEM, n=5), which was significantly higher than that of the
normoxic controls (P=0.0071). In contrast, the hypoxic
animals treated with NiCl2 did not develop
pulmonary hypertension after 1 week of hypoxic exposure. Their
systolic RVP was 10.5±3 mm Hg (mean±SEM, n=4), which
was not statistically different from the normoxic controls.
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Effect of HO-1 Induction on Systemic Circulation
To determine whether the effect of HO-1 induction was
restricted to the pulmonary circulation or affected the
systemic circulation, we measured MAP in conscious rats. MAP was not
significantly affected by a 1-week exposure to hypoxia
(128.2±4.9 mm Hg in normoxia versus 131±6.1 mm Hg in
hypoxia, P>0.05, n=5 per group). Treatment with
NiCl2 in the setting of hypoxia led to a
small but significant reduction in MAP (108.6±6.6 mm Hg,
P<0.05, n=5) (Figure 2B
). Treatment of normoxic
animals with NiCl2 did not affect MAP
significantly (120.2±2.3 mm Hg, n=5).
Prevention of Pulmonary Vascular Remodeling
Increased thickness of pulmonary arterioles due to
SMC hypertrophy and hyperplasia is the structural hallmark
of pulmonary hypertension.27 As shown in Figure 3A, pulmonary arterioles in
normoxic animals were thin, whereas after 1 week of hypoxic exposure
they developed increased medial thickness characteristic of
pulmonary hypertension (Figure 3B). In contrast, the
hypoxic animals treated with NiCl2 (Figure 3C) or hemin (Figure 3D) had markedly reduced vascular
remodeling and the medial thickness of their pulmonary
arterioles was comparable with that of normoxic controls.
Quantification of these structural changes in several lung sections of
all of the animals exposed to the 3 different conditions revealed
significantly increased medial thickness of pulmonary
arterioles in hypoxic animals compared with normoxic controls (49%
versus 26%, P<0.05), but essentially unchanged from
baseline normoxic medial thickness in the hypoxic animals treated with
NiCl2 (26% versus 36%; NS) (Figure 4).
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Effect of HO-1 Induction in Circulating Concentrations of
cGMP
CO is known to activate guanylyl cyclase and increase cGMP
levels in SMCs.6 cGMP in turn mediates CO-induced effects
such as vasodilation and inhibition of ET-1, PDGF-B, and E2F-1
transcription.9 10 To determine whether treatment with
HO-1 inducers leads to increased levels of biologically active CO, we
measured circulating cGMP concentrations in the animals. We found that
treatment with NiCl2 led to significantly
higher circulating cGMP concentrations compared with control animals
under normoxia (26.2 versus 8.7 pmol/mL, respectively,
P<0.05) (Figure 5). In the
hypoxic setting, treatment with NiCl2 also
increased circulating cGMP levels, but the difference did not reach
statistical significance compared with hypoxic controls (15.5 versus
9.3 pmol/mL, respectively, P>0.05). There was no difference
in cGMP levels between normoxic and hypoxic animals (8.7 versus 9.3
pmol/mL, respectively, P>0.05).
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Discussion |
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Regulation of pulmonary vascular tone and homeostasis involves a number of vasoconstrictors, relaxing agents, and growth factors that are released from different cell types in the vasculature and interact through feedback loops. Hypoxia is known to regulate these cellular interactions mainly by modifying gene expression.28 In culture, hypoxia induces the expression of vasoconstrictors such as ET-1 and PDGF-B21 29 and inhibits the production of the vasodilator NO via inhibition of NO synthase gene expression.30 Hypoxia thus may shift the balance of vasoactive mediators toward agents promoting vasoconstriction and structural remodeling, as seen in pulmonary hypertension. In this study, we found that HO-1, which catalyzes the production of CO and bilirubin, is transiently induced by hypoxia in the lung in vivo. We demonstrated that treatment with NiCl2 or hemin, each of which is an inducer of HO-1, enhanced and sustained high levels of HO-1 expression in the lung and led to increased HO enzymatic activity with increased levels of circulating cGMP. In the hypoxic setting, these inducers protected rats from developing pulmonary hypertension and prevented the accompanying structural remodeling of pulmonary arterioles. An earlier study by Sacerdoti et al,31 using tin to induce HO, prevented the development of systemic hypertension in spontaneously hypertensive rats. The mechanism(s) implicated in that study included depletion of heme, the substrate of HO, resulting in decreased hemoproteins such as renal cytochrome P-450 and reduced free arachidonic acid metabolites that have prohypertensive properties. It is possible that increased levels of CO, the enzymatic product of HO, may have also contributed to the reduction in blood pressure in that animal model.
The mechanism(s) by which sustained HO-1 expression prevented hypoxic pulmonary hypertension remain to be elucidated. These may include direct vasodilatory and antiproliferative effects of CO, the product of HO-1, as well as antioxidant properties of bilirubin, also released from the breakdown of heme by HO-1. It is likely that reactive oxygen species may contribute to the pathogenesis of hypoxic pulmonary hypertension and bilirubin may limit this process. Indeed, the antioxidant activity of bilirubin is significantly enhanced under low oxygen conditions (2% O2) compared with that at 20% O2.14 Alternatively, the increased local production of CO in the lung may lead to increased lung cGMP levels, which are known to mediate the vasodilator and antiproliferative effects of CO. In our in vitro studies, CO/cGMP was shown to inhibit the cell cycle–specific transcription factor E2F-1; to reduce SMC proliferation in culture10 ; and to suppress the hypoxic induction of ET-1, PDGF-B, and vascular endothelial growth factor by endothelial cells.9 32 CO interferes with cell cycle progression directly at the G1/S phase via its effect on E2F-1 transcription, as well as indirectly at the G0/G1 phase via its effect on mitogen transcription (ET-1 and PDGF-B). Similar mechanisms may limit medial SMC hyperplasia in vivo.
We found increased circulating cGMP levels in response to treatment with HO-1 inducers under normoxia, demonstrating that the increase in HO-1 protein resulted in enhanced biologic activity. A suppression of the NO pathway may explain the absence of a more dramatic increase in cGMP levels under hypoxia when HO-1 inducers were used. Indeed, endothelial cell–derived NO is the molecule classically described to control cGMP content in the vasculature under basal conditions. In cases of vascular injury such as pulmonary hypertension, endothelial cell–derived NO production may be reduced,33 34 leading to decreased cGMP.23 We speculate that vascular SMC-derived CO may represent a compensatory response of the vasculature during hypoxia when NO production is suppressed. NO and CO share common properties of vasodilation and have been reported to inhibit SMC growth as well as to regulate gene expression. Both were shown to inhibit the DNA-binding activity of hypoxia-inducible factor-1,32 35 a key transcription factor in the hypoxic signaling pathway. It is thus reasonable to speculate that a critical balance of NO and CO is required for the maintenance of vascular tone and vessel wall integrity under physiological as well as pathophysiological conditions of hypoxia. The unraveling of the molecular mechanisms underlying hypoxia-induced vascular changes is likely to lead to the development of novel approaches in the management of disorders characterized by abnormal pulmonary vascular tone and structure such as pulmonary hypertension.
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Acknowledgments |
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H.C. was supported by the National Institute of Child Health and Human Development Child Health Research Center New Project Development Funds as a Janeway Scholar. M.A.P. was supported by an American Heart Association Grant-in-Aid, by NIH Grant K08HL03194, and by Bristol-Myers Squibb Pharmaceutical Research Institute. S.K. was supported by the American Heart Association and by NIH Grants R01 HL55454 and SCOR IP50 HL 56398. We thank Jessica Johnson for her expert assistance in the preparation of the manuscript.
Received February 4, 2000; accepted April 20, 2000.
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References |
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|---|
1. Marks GS, Brien JF, Nakatsu K, McLaughlin BE. Does carbon monoxide have a physiological function? Trends Pharmacol Sci. 1991;12:185–188.[Medline] [Order article via Infotrieve]
2.
Shibahara S, Muller R, Taguchi H, Yoshida T. Cloning
and expression of cDNA for rat heme oxygenase. Proc
Natl Acad Sci U S A. 1985;82:7865–7869.
3.
Trakshel GM, Kutty RK, Maines MD. Purification and
characterization of the major constitutive form of testicular heme
oxygenase. J Biol Chem. 1986;261:11131–11137.
4. McCoubrey WK, Huang TJ, Maines MD. Isolation and characterization of a cDNA from the rat brain that encodes hemoprotein heme oxygenase-3. Eur J Biochem. 1997;247:725–732.[Medline] [Order article via Infotrieve]
5.
Verma A, Hirsch DJ, Glatt CE, Ronnett GV, Snyder SH.
Carbon monoxide: a putative neural messenger. Science. 1993;259:381–384.
6.
Morita T, Perrella MA, Lee M-E, Kourembanas S. Smooth
muscle cell-derived carbon monoxide is a regulator of vascular cGMP.
Proc Natl Acad Sci U S A. 1995;92:1475–1479.
7. Ramos KS, Lin H, McGrath JJ. Modulation of cyclic monophosphate levels in cultured aortic smooth muscle cells by carbon monoxide. Biochem Pharmacol. 1989;38:1368–1370.[Medline] [Order article via Infotrieve]
8. Vedernikov YP, Graser T, Vanin AF. Similar endothelium-independent arterial relaxation by carbon monoxide and nitric oxide. Biomed Biochim Acta. 1989;48:601–603.[Medline] [Order article via Infotrieve]
9. Morita T, Kourembanas S. Endothelial cell expression of vasoconstrictors and growth factors is regulated by smooth muscle cell-derived carbon monoxide. J Clin Invest. 1995;96:2676–2682.
10.
Morita T, Mitsialis SA, Koike H, Liu Y, Kourembanas S.
Carbon monoxide controls the proliferation of hypoxic vascular smooth
muscle cells. J Biol Chem. 1997;272:32804–32809.
11. Shibahara S. Regulation of heme oxygenase gene expression. Semin Hematol. 1988;25:370–376.[Medline] [Order article via Infotrieve]
12. Maines MD. Heme oxygenase: function, multiplicity, regulatory mechanisms, and clinical applications. FASEB J. 1988;2:2557–2568.[Abstract]
13. Rodgers PA, Stevenson DK. Developmental biology of heme oxygenase. Clin Perinatol. 1990;17:275–291.[Medline] [Order article via Infotrieve]
14.
Stocker R, Yamamoto Y, McDonagh AF, Glazer AN, Ames BN.
Bilirubin is an antioxidant of possible
physiological importance. Science. 1987;235:1043–1046.
15.
Elton TS, Oparil S, Taylor GR, Hicks PH, Yang RH, Jin
H, Chen YF. Normobaric hypoxia stimulates endothelin-1 gene
expression in the rat. Am J Physiol. 1992;263:R1260–R1264.
16.
Morrell NW, Danilov SM, Satyan KB, Morris KG, Stenmark
KR. Right ventricular angiotensin converting
enzyme activity and expression is increased during hypoxic
pulmonary hypertension. Cardiovasc Res. 1997;34:393–403.
17. Le Cras TD, Tyler RC, Horan MP, Morris KG, Tuder RM, McMurtry IF, Johns RA, Abman SH. Effects of chronic hypoxia and altered hemodynamics on endothelial nitric oxide synthase expression in the adult rat lung. J Clin Invest. 1998;101:795–801.[Medline] [Order article via Infotrieve]
18.
Xue C, Rengasamy A, Le Cras TD, Koberna PA, Dailey GC,
Johns RA. Distribution of NOS in normoxic vs hypoxic rat lung:
upregulation of NOS by chronic hypoxia. Am J
Physiol. 1994;267:L667–L678.
19.
Christou H, Yoshida A, Arthur V, Morita T, Kourembanas
S. Increased vascular endothelial growth factor
production in the lungs of rats with hypoxia-induced
pulmonary hypertension. Am J Respir Cell Mol
Biol. 1998;18:768–776.
20. Chomczynski P, Sacchi N. Single-step method of RNA isolation by guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987;162:156–159.[Medline] [Order article via Infotrieve]
21. Kourembanas S, Hannan RL, Faller DV. Oxygen tension regulates the expression of the platelet-derived growth factor-B chain gene in human endothelial cells. J Clin Invest. 1990;86:670–674.
22.
Shi C, Lee W-S, Russell ME, Zhang D, Fletcher DL,
Newell JB, Haber E. Hypercholesterolemia
exacerbates transplant arteriosclerosis via
increased neointimal smooth muscle cell accumulation:
studies in apolipoprotein E knockout mice. Circulation. 1997;96:2722–2728.
23. Christou H, Adatia I, Van Marter LJ, Kane JW, Thompson JE, Stark AR, Wessel DL, Kourembanas S. Effect of inhaled nitric oxide on endothelin-1 and cyclic guanosine 5'-monophosphate plasma concentrations in newborn infants with persistent pulmonary hypertension. J Pediatr. 1997;130:603–611.[Medline] [Order article via Infotrieve]
24.
Kappas A, Maines MD. Tin: a potent inducer of heme
oxygenase in kidney. Science. 1976;192:60–62.
25. Sunderman FWJ, Reid MC, Bibeau LM, Linden JV. Nickel induction of microsomal heme oxygenase activity in rodents. Toxicol Appl Pharmacol. 1983;68:87–95.[Medline] [Order article via Infotrieve]
26. Sunderman FWJ. Metal induction of heme oxygenase. Ann N Y Acad Sci. 1987;514:65–80.[Medline] [Order article via Infotrieve]
27. Jones RC, Reid LM. Structural basis of pulmonary hypertension. Curr Pulmonol. 1987;8:175–210.
28. Kourembanas S, Morita T, Liu Y, Christou H. Mechanisms by which oxygen regulates gene expression and cell-cell interaction in the vasculature. Kidney Int. 1997;51:438–443.[Medline] [Order article via Infotrieve]
29. Kourembanas S, Marsden PA, McQuillan LP, Faller DV. Hypoxia induces endothelin gene expression and secretion in cultured human endothelium. J Clin Invest. 1991;88:1054–1057.
30.
McQuillan LP, Leung GK, Marsden PA, Kostyk SK,
Kourembanas S. Hypoxia inhibits expression of eNOS via
transcriptional and posttranscriptional mechanisms. Am J
Physiol. 1994;267:H1921–H1927.
31.
Sacerdoti D, Escalante B, Abraham NG, McGiff JC, Levere
RD, Schwartzman ML. Treatment with tin prevents the development of
hypertension in spontaneously hypertensive rats. Science. 1989;243:388–390.
32.
Liu Y, Christou H, Morita T, Laughner E, Semenza GL,
Kourembanas S. Carbon monoxide and nitric oxide suppress the hypoxic
induction of vascular endothelial growth factor gene
via the 5' enhancer. J Biol Chem. 1998;273:15257–15262.
33. Vosatka RJ, Kashyap S, Trifiletti RR. Arginine deficiency accompanies persistent pulmonary hypertension of the newborn. Biol Neonate. 1994;66:65–70.[Medline] [Order article via Infotrieve]
34. Dollberg S, Warner BW, Myatt L. Urinary nitrite and nitrate concentrations in patients with idiopathic persistent pulmonary hypertension of the newborn and effect of extracorporeal membrane oxygenation. Pediatr Res. 1995;37:31–34.[Medline] [Order article via Infotrieve]
35.
Sogawa K, Numayama-Tsuruta K, Ema M, Abe M, Abe H,
Fujii-Kuriyama Y. Inhibition of hypoxia-inducible factor 1
activity by nitric oxide donors in hypoxia. Proc Natl
Acad Sci U S A. 1998;95:7368–7373.
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|
 |
|
 X. Yang, P. J. Lee, L. Long, R. C. Trembath, and N. W. Morrell BMP4 Induces HO-1 via a Smad-Independent, p38MAPK-Dependent Pathway in Pulmonary Artery Myocytes Am. J. Respir. Cell Mol. Biol., November 1, 2007; 37(5): 598 - 605. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Ito, T. Okada, H. Miyashita, T. Nomoto, M. Nonaka-Sarukawa, R. Uchibori, Y. Maeda, M. Urabe, H. Mizukami, A. Kume, et al. Interleukin-10 Expression Mediated by an Adeno-Associated Virus Vector Prevents Monocrotaline-Induced Pulmonary Arterial Hypertension in Rats Circ. Res., September 28, 2007; 101(7): 734 - 741. [Abstract] [Full Text] [PDF]
|
|
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|
|
|
L. E. Fredenburgh, M. A. Perrella, and S. A. Mitsialis The Role of Heme Oxygenase-1 in Pulmonary Disease Am. J. Respir. Cell Mol. Biol., February 1, 2007; 36(2): 158 - 165. [Abstract] [Full Text] [PDF]
|
|
|
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 |
|
 B. S. Zuckerbraun, B. Y. Chin, B. Wegiel, T. R. Billiar, E. Czsimadia, J. Rao, L. Shimoda, E. Ifedigbo, S. Kanno, and L. E. Otterbein Carbon monoxide reverses established pulmonary hypertension J. Exp. Med., September 4, 2006; 203(9): 2109 - 2119. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. A. Pryor, K. N. Houk, C. S. Foote, J. M. Fukuto, L. J. Ignarro, G. L. Squadrito, and K. J. A. Davies Free radical biology and medicine: it's a gas, man! Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2006; 291(3): R491 - R511. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Wu, M. S. Chang, S. A. Mitsialis, and S. Kourembanas Hypoxia Regulates Bone Morphogenetic Protein Signaling Through C-Terminal-Binding Protein 1 Circ. Res., August 4, 2006; 99(3): 240 - 247. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. W. Ryter, J. Alam, and A. M. K. Choi Heme Oxygenase-1/Carbon Monoxide: From Basic Science to Therapeutic Applications Physiol Rev, April 1, 2006; 86(2): 583 - 650. [Abstract] [Full Text] [PDF]
|
|
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|
 |
|
 R. O. D. Achcar, Y. Demura, P. R. Rai, L. Taraseviciene-Stewart, M. Kasper, N. F. Voelkel, and C. D. Cool Loss of Caveolin and Heme Oxygenase Expression in Severe Pulmonary Hypertension Chest, March 1, 2006; 129(3): 696 - 705. [Abstract] [Full Text] [PDF]
|
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A. Rebel, S. Cao, H. Kwansa, S. Dore, E. Bucci, and R. C. Koehler Dependence of acetylcholine and ADP dilation of pial arterioles on heme oxygenase after transfusion of cell-free polymeric hemoglobin Am J Physiol Heart Circ Physiol, March 1, 2006; 290(3): H1027 - H1037. [Abstract] [Full Text] [PDF]
|
|
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|
|
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I. R. Preston, N. S. Hill, R. R. Warburton, and B. L. Fanburg Role of 12-lipoxygenase in hypoxia-induced rat pulmonary artery smooth muscle cell proliferation Am J Physiol Lung Cell Mol Physiol, February 1, 2006; 290(2): L367 - L374. [Abstract] [Full Text] [PDF]
|
|
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 |
|
 P. Achouh, S. Simonet, C. Badier-Commander, C. Chardigny, C. Vayssettes-Courchay, R. Zegdi, Z. Khabbaz, J.-N. Fabiani, and T. J. Verbeuren The induction of heme oxygenase 1 decreases contractility in human internal thoracic artery and radial artery grafts J. Thorac. Cardiovasc. Surg., December 1, 2005; 130(6): 1573 - 1580. [Abstract] [Full Text] [PDF]
|
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|
|
 |
|
 L. Wu and R. Wang Carbon Monoxide: Endogenous Production, Physiological Functions, and Pharmacological Applications Pharmacol. Rev., December 1, 2005; 57(4): 585 - 630. [Abstract] [Full Text] [PDF]
|
|
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|
|
|
D. Morse and A. M. K. Choi Heme Oxygenase-1: From Bench to Bedside Am. J. Respir. Crit. Care Med., September 15, 2005; 172(6): 660 - 670. [Abstract] [Full Text] [PDF]
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C. Taille, J. El-Benna, S. Lanone, J. Boczkowski, and R. Motterlini Mitochondrial Respiratory Chain and NAD(P)H Oxidase Are Targets for the Antiproliferative Effect of Carbon Monoxide in Human Airway Smooth Muscle J. Biol. Chem., July 8, 2005; 280(27): 25350 - 25360. [Abstract] [Full Text] [PDF]
|
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|
|
|
H. Christou, N. Bailey, M. S. Kluger, S. A. Mitsialis, and S. Kourembanas Extracellular acidosis induces heme oxygenase-1 expression in vascular smooth muscle cells Am J Physiol Heart Circ Physiol, June 1, 2005; 288(6): H2647 - H2652. [Abstract] [Full Text] [PDF]
|
|
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|
|
E. Dubuis, M. Potier, R. Wang, and C. Vandier Continuous inhalation of carbon monoxide attenuates hypoxic pulmonary hypertension development presumably through activation of BKCa channels Cardiovasc Res, February 15, 2005; 65(3): 751 - 761. [Abstract] [Full Text] [PDF]
|
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|
|
 |
|
 M. Imamura, B. Luo, J. Limbird, A. Vitello, M. Oka, D. D. Ivy, I. F. McMurtry, C. V. Garat, M. B. Fallon, and E. P. Carter Hypoxic pulmonary hypertension is prevented in rats with common bile duct ligation J Appl Physiol, February 1, 2005; 98(2): 739 - 747. [Abstract] [Full Text] [PDF]
|
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|
|
|
V. Govindaraju, H. Teoh, Q. Hamid, P. Cernacek, and M. E. Ward Interaction between endothelial heme oxygenase-2 and endothelin-1 in altered aortic reactivity after hypoxia in rats Am J Physiol Heart Circ Physiol, February 1, 2005; 288(2): H962 - H970. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. L. Hartsfield, I. F. McMurtry, D. D. Ivy, K. G. Morris, S. Vidmar, D. M. Rodman, and K. A. Fagan Cardioprotective and vasomotor effects of HO activity during acute and chronic hypoxia Am J Physiol Heart Circ Physiol, November 1, 2004; 287(5): H2009 - H2015. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. S. Wong and A. J. Van der Kogel MECHANISMS OF RADIATION INJURY TO THE CENTRAL NERVOUS SYSTEM: IMPLICATIONS FOR NEUROPROTECTION Mol. Interv., October 1, 2004; 4(5): 273 - 284. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Fujimoto, M. Ohno, S. Ayabe, H. Kobayashi, N. Ishizaka, H. Kimura, K.-i. Yoshida, and R. Nagai Carbon Monoxide Protects Against Cardiac Ischemia--Reperfusion Injury In Vivo via MAPK and Akt--eNOS Pathways Arterioscler Thromb Vasc Biol, October 1, 2004; 24(10): 1848 - 1853. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Yu, I. Fantozzi, C. V. Remillard, J. W. Landsberg, N. Kunichika, O. Platoshyn, D. D. Tigno, P. A. Thistlethwaite, L. J. Rubin, and J. X.-J. Yuan Enhanced expression of transient receptor potential channels in idiopathic pulmonary arterial hypertension PNAS, September 21, 2004; 101(38): 13861 - 13866. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Matsui, T. Shimosawa, K. Itakura, X. Guanqun, K. Ando, and T. Fujita Adrenomedullin Can Protect Against Pulmonary Vascular Remodeling Induced by Hypoxia Circulation, May 11, 2004; 109(18): 2246 - 2251. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. J. Gibbons and G. Farrugia The role of carbon monoxide in the gastrointestinal tract J. Physiol., April 15, 2004; 556(2): 325 - 336. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Zhang, J. I. Kaide, L. Yang, H. Jiang, S. Quan, R. Kemp, W. Gong, M. Balazy, N. G. Abraham, and A. Nasjletti CO modulates pulmonary vascular response to acute hypoxia: relation to endothelin Am J Physiol Heart Circ Physiol, January 1, 2004; 286(1): H137 - H144. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Taille, A. Almolki, M. Benhamed, C. Zedda, J. Megret, P. Berger, G. Leseche, E. Fadel, T. Yamaguchi, R. Marthan, et al. Heme Oxygenase Inhibits Human Airway Smooth Muscle Proliferation via a Bilirubin-dependent Modulation of ERK1/2 Phosphorylation J. Biol. Chem., July 11, 2003; 278(29): 27160 - 27168. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. S. Naik and B. R. Walker Heme oxygenase-mediated vasodilation involves vascular smooth muscle cell hyperpolarization Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H220 - H228. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y.-H. Chen, S.-F. Yet, and M. A. Perrella Role of Heme Oxygenase-1 in the Regulation of Blood Pressure and Cardiac Function Experimental Biology and Medicine, May 1, 2003; 228(5): 447 - 453. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Li Volti, F. Seta, M. L. Schwartzman, A. Nasjletti, and N. G. Abraham Heme Oxygenase Attenuates Angiotensin II-Mediated Increase in Cyclooxygenase-2 Activity in Human Femoral Endothelial Cells Hypertension, March 1, 2003; 41(3): 715 - 719. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Yang, K. K. K. Sheares, N. Davie, P. D. Upton, G. W. Taylor, J. Horsley, J. Wharton, and N. W. Morrell Hypoxic Induction of Cox-2 Regulates Proliferation of Human Pulmonary Artery Smooth Muscle Cells Am. J. Respir. Cell Mol. Biol., December 1, 2002; 27(6): 688 - 696. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Morse and A. M. K. Choi Heme Oxygenase-1 . The "Emerging Molecule" Has Arrived Am. J. Respir. Cell Mol. Biol., July 1, 2002; 27(1): 8 - 16. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Dubuis, M. Gautier, A. Melin, M. Rebocho, C. Girardin, P. Bonnet, and C. Vandier Chronic carbon monoxide enhanced IbTx-sensitive currents in rat resistance pulmonary artery smooth muscle cells Am J Physiol Lung Cell Mol Physiol, July 1, 2002; 283(1): L120 - L129. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. S. Naik and B. R. Walker Homogeneous segmental profile of carbon monoxide-mediated pulmonary vasodilation in rats Am J Physiol Lung Cell Mol Physiol, December 1, 2001; 281(6): L1436 - L1443. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Foresti, H. Goatly, C. J. Green, and R. Motterlini Role of heme oxygenase-1 in hypoxia-reoxygenation: requirement of substrate heme to promote cardioprotection Am J Physiol Heart Circ Physiol, November 1, 2001; 281(5): H1976 - H1984. [Abstract] [Full Text] [PDF]
|
|
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|
|
|
A. M.K. Choi Heme Oxygenase-1 Protects the Heart Circ. Res., July 20, 2001; 89(2): 105 - 107. [Full Text] [PDF]
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|
|
|
|
|
E. Mazza, S. Thakkar-Varia, C. A. Tozzi, and J. A. Neubauer Expression of heme oxygenase in the oxygen-sensing regions of the rostral ventrolateral medulla J Appl Physiol, July 1, 2001; 91(1): 379 - 385. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. L. Jernigan, T. L. O'Donaughy, and B. R. Walker Correlation of HO-1 expression with onset and reversal of hypoxia-induced vasoconstrictor hyporeactivity Am J Physiol Heart Circ Physiol, July 1, 2001; 281(1): H298 - H307. [Abstract] [Full Text] [PDF]
|
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|
P. Wiesel, A. P. Patel, I. M. Carvajal, Z. Y. Wang, A. Pellacani, K. Maemura, N. DiFonzo, H. G. Rennke, M. D. Layne, S.-F. Yet, et al. Exacerbation of Chronic Renovascular Hypertension and Acute Renal Failure in Heme Oxygenase-1-Deficient Mice Circ. Res., May 25, 2001; 88(10): 1088 - 1094. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Imai, T. Morita, T. Shindo, R. Nagai, Y. Yazaki, H. Kurihara, M. Suematsu, and S. Katayama Vascular Smooth Muscle Cell-Directed Overexpression of Heme Oxygenase-1 Elevates Blood Pressure Through Attenuation of Nitric Oxide-Induced Vasodilation in Mice Circ. Res., July 6, 2001; 89(1): 55 - 62. [Abstract] [Full Text] [PDF]
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A. Keegan, I. Morecroft, D. Smillie, M. N. Hicks, and M. R. MacLean Contribution of the 5-HT1B Receptor to Hypoxia-Induced Pulmonary Hypertension: Converging Evidence Using 5-HT1B-Receptor Knockout Mice and the 5-HT1B/1D-Receptor Antagonist GR127935 Circ. Res., December 7, 2001; 89(12): 1231 - 1239. [Abstract] [Full Text] [PDF]
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