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Rajgarhia A, Ayasolla KR, Zaghloul N, Lopez Da Re JM, Miller EJ, Ahmed M. Extracellular Superoxide Dismutase (EC-SOD) Regulates Gene Methylation and Cardiac Fibrosis During Chronic Hypoxic Stress. Front Cardiovasc Med 2021; 8:669975. [PMID: 34136546 PMCID: PMC8202000 DOI: 10.3389/fcvm.2021.669975] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/16/2021] [Indexed: 12/12/2022] Open
Abstract
Chronic hypoxic stress induces epigenetic modifications mainly DNA methylation in cardiac fibroblasts, inactivating tumor suppressor genes (RASSF1A) and activating kinases (ERK1/2) leading to fibroblast proliferation and cardiac fibrosis. The Ras/ERK signaling pathway is an intracellular signal transduction critically involved in fibroblast proliferation. RASSF1A functions through its effect on downstream ERK1/2. The antioxidant enzyme, extracellular superoxide dismutase (EC-SOD), decreases oxidative stress from chronic hypoxia, but its effects on these epigenetic changes have not been fully explored. To test our hypothesis, we used an in-vitro model: wild-type C57B6 male mice (WT) and transgenic males with an extra copy of human hEC-SOD (TG). The studied animals were housed in hypoxia (10% O2) for 21 days. The right ventricular tissue was studied for cardiac fibrosis markers using RT-PCR and Western blot analyses. Primary C57BL6 mouse cardiac fibroblast tissue culture was used to study the in-vitro model, the downstream effects of RASSF-1 expression and methylation, and its relation to ERK1/2. Our findings showed a significant increase in cardiac fibrosis markers: Collagen 1, alpha smooth muscle actin (ASMA), and SNAIL, in the WT hypoxic animals as compared to the TG hypoxic group (p < 0.05). The expression of DNA methylation enzymes (DNMT 1&3b) was significantly increased in the WT hypoxic mice as compared to the hypoxic TG mice (p < 0.001). RASSF1A expression was significantly lower and ERK1/2 was significantly higher in hypoxia WT compared to the hypoxic TG group (p < 0.05). Use of SiRNA to block RASSF1A gene expression in murine cardiac fibroblast tissue culture led to increased fibroblast proliferation (p < 0.05). Methylation of the RASSF1A promoter region was significantly reduced in the TG hypoxic group compared to the WT hypoxic group (0.59 vs. 0.75, respectively). Based on our findings, we can speculate that EC-SOD significantly attenuates RASSF1A gene methylation and can alleviate cardiac fibrosis induced by hypoxia.
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Affiliation(s)
- Ayan Rajgarhia
- School of Medicine, Children's Mercy Hospital and University of Missouri-Kansas City, Kansas City, MO, United States
| | | | - Nahla Zaghloul
- Neonatal Division, University of Arizona, Tucson, AZ, United States
| | - Jorge M Lopez Da Re
- Neonatal Division, Orlando, Nemours Children's Hospital, Orlando, FL, United States
| | | | - Mohamed Ahmed
- Neonatal Division, University of Arizona, Tucson, AZ, United States
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Adão R, Mendes-Ferreira P, Maia-Rocha C, Santos-Ribeiro D, Rodrigues PG, Vidal-Meireles A, Monteiro-Pinto C, Pimentel LD, Falcão-Pires I, De Keulenaer GW, Leite-Moreira AF, Brás-Silva C. Neuregulin-1 attenuates right ventricular diastolic stiffness in experimental pulmonary hypertension. Clin Exp Pharmacol Physiol 2018; 46:255-265. [PMID: 30339273 DOI: 10.1111/1440-1681.13043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 12/28/2022]
Abstract
We have previously shown that treatment with recombinant human neuregulin-1 (rhNRG-1) improves pulmonary arterial hypertension (PAH) in a monocrotaline (MCT)-induced animal model, by decreasing pulmonary arterial remodelling and endothelial dysfunction, as well as by restoring right ventricular (RV) function. Additionally, rhNRG-1 treatment showed direct myocardial anti-remodelling effects in a model of pressure loading of the RV without PAH. This work aimed to study the intrinsic cardiac effects of rhNRG-1 on experimental PAH and RV pressure overload, and more specifically on diastolic stiffness, at both the ventricular and cardiomyocyte level. We studied the effects of chronic rhNRG-1 treatment on ventricular passive stiffness in RV and LV samples from MCT-induced PAH animals and in the RV from animals with compensated and decompensated RV hypertrophy, through a mild and severe pulmonary artery banding (PAB). We also measured passive tension in isolated cardiomyocytes and quantified the expression of myocardial remodelling-associated genes and calcium handling proteins. Chronic rhNRG-1 treatment decreased passive tension development in RV and LV isolated from animals with MCT-induced PAH. This decrease was associated with increased phospholamban phosphorylation, and with attenuation of the expression of cardiac maladaptive remodelling markers. Finally, we showed that rhNRG-1 therapy decreased RV remodelling and cardiomyocyte passive tension development in PAB-induced RV hypertrophy animals, without compromising cardiac function, pointing to cardiac-specific effects in both hypertrophy stages. In conclusion, we demonstrated that rhNRG-1 treatment decreased RV intrinsic diastolic stiffness, through the improvement of calcium handling and cardiac remodelling signalling.
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Affiliation(s)
- Rui Adão
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Pedro Mendes-Ferreira
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Carolina Maia-Rocha
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Diana Santos-Ribeiro
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Patrícia Gonçalves Rodrigues
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - André Vidal-Meireles
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Cláudia Monteiro-Pinto
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Luís D Pimentel
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Inês Falcão-Pires
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | | | - Adelino F Leite-Moreira
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Carmen Brás-Silva
- Department of Surgery and Physiology, UnIC-Cardiovascular Research Centre, Faculty of Medicine, University of Porto, Porto, Portugal.,Faculty of Nutrition and Food Sciences, University of Porto, Porto, Portugal
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Velotta JP, Ivy CM, Wolf CJ, Scott GR, Cheviron ZA. Maladaptive phenotypic plasticity in cardiac muscle growth is suppressed in high-altitude deer mice. Evolution 2018; 72:2712-2727. [PMID: 30318588 DOI: 10.1111/evo.13626] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 09/12/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022]
Abstract
How often phenotypic plasticity acts to promote or inhibit adaptive evolution is an ongoing debate among biologists. Recent work suggests that adaptive phenotypic plasticity promotes evolutionary divergence, though several studies have also suggested that maladaptive plasticity can potentiate adaptation. The role of phenotypic plasticity, adaptive, or maladaptive, in evolutionary divergence remains controversial. We examined the role of plasticity in evolutionary divergence between two species of Peromyscus mice that differ in native elevations. We used cardiac mass as a model phenotype, since ancestral hypoxia-induced responses of the heart may be both adaptive and maladaptive at high-altitude. While left ventricle growth should enhance oxygen delivery to tissues, hypertrophy of the right ventricle can lead to heart failure and death. We compared left- and right-ventricle plasticity in response to hypoxia between captive-bred P. leucopus (representing the ancestral lowland condition) and P. maniculatus from high-altitude. We found that maladaptive ancestral plasticity in right ventricle hypertrophy is reduced in high-altitude deer mice. Analysis of the heart transcriptome suggests that changes in expression of inflammatory signaling genes, particularly interferon regulatory factors, contribute to the suppression of right ventricle hypertrophy. We found weak evidence that adaptive plasticity of left ventricle mass contributes to evolution. Our results suggest that selection to suppress ancestral maladaptive plasticity plays a role in adaptation.
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Affiliation(s)
- Jonathan P Velotta
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
| | - Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Cole J Wolf
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
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Uenoyama M, Ogata S, Nakanishi K, Kanazawa F, Hiroi S, Tominaga S, Seo A, Matsui T, Kawai T, Suzuki S. Protein kinase C mRNA and protein expressions in hypobaric hypoxia-induced cardiac hypertrophy in rats. Acta Physiol (Oxf) 2010; 198:431-40. [PMID: 19995357 DOI: 10.1111/j.1748-1716.2009.02064.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIM Protein kinase C (PKC), cloned as a serine/threonine kinase, plays key roles in diverse intracellular signalling processes and in cardiovascular remodelling during pressure overload or volume overload. We looked for correlations between changes in PKC isoforms (levels and/or subcellular distributions) and cardiac remodelling during experimental hypobaric hypoxic environment (HHE)-induced pulmonary hypertension. METHODS To study the PKC system in the heart during HHE, 148 male Wistar rats were housed for up to 21 days in a chamber at the equivalent of 5500 m altitude level (10% O(2)). RESULTS At 14 or more days of exposure to HHE, pulmonary arterial pressure (PAP) was significantly increased. In the right ventricle (RV): (1) the expression of PKC-alpha protein in the cytosolic and membrane fractions was increased at 3-14 days and at 5-7 days of exposure respectively; (ii) the cytosolic expression of PKC-delta protein was increased at 1-5, 14 and 21 days of exposure; (3) the membrane expressions of the proteins were decreased at 14-21 (PKC-betaII), 14-21 (PKC-gamma), and 0.5-5 and 21 (PKC-epsilon) days of exposure; (4) the expression of the active form of PKC-alpha protein on the plasma membrane was increased at 3 days of exposure (based on semiquantitative analysis of the immunohistochemistry). In the left ventricle, the expressions of the PKC mRNAs, and of their cytosolic and membrane proteins, were almost unchanged. The above changes in PKC-alpha, which were strongly evident in the RV, occurred alongside the increase in PAP. CONCLUSION PKC-alpha may help to modulate the right ventricular hypertrophy caused by pulmonary hypertension in HHE.
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Affiliation(s)
- M Uenoyama
- National Defense Medical College Research Institute, Tokorozawa, Japan
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Bogaard HJ, Natarajan R, Henderson SC, Long CS, Kraskauskas D, Smithson L, Ockaili R, McCord JM, Voelkel NF. Chronic Pulmonary Artery Pressure Elevation Is Insufficient to Explain Right Heart Failure. Circulation 2009; 120:1951-60. [DOI: 10.1161/circulationaha.109.883843] [Citation(s) in RCA: 402] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
The most important determinant of longevity in pulmonary arterial hypertension is right ventricular (RV) function, but in contrast to experimental work elucidating the pathobiology of left ventricular failure, there is a paucity of data on the cellular and molecular mechanisms of RV failure.
Methods and Results—
A mechanical animal model of chronic progressive RV pressure overload (pulmonary artery banding, not associated with structural alterations of the lung circulation) was compared with an established model of angioproliferative pulmonary hypertension associated with fatal RV failure. Isolated RV pressure overload induced RV hypertrophy without failure, whereas in the context of angioproliferative pulmonary hypertension, RV failure developed that was associated with myocardial apoptosis, fibrosis, a decreased RV capillary density, and a decreased vascular endothelial growth factor mRNA and protein expression despite increased nuclear stabilization of hypoxia-induced factor-1α. Induction of myocardial nuclear factor E2-related factor 2 and heme-oxygenase 1 with a dietary supplement (Protandim) prevented fibrosis and capillary loss and preserved RV function despite continuing pressure overload.
Conclusion—
These data brought into question the commonly held concept that RV failure associated with pulmonary hypertension is due strictly to the increased RV afterload.
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Affiliation(s)
- Harm J. Bogaard
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Ramesh Natarajan
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Scott C. Henderson
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Carlin S. Long
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Donatas Kraskauskas
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Lisa Smithson
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Ramzi Ockaili
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Joe M. McCord
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Norbert F. Voelkel
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
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6
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Uenoyama M, Ogata S, Nakanishi K, Kanazawa F, Hiroi S, Tominaga S, Kanatani Y, Seo A, Matsui T, Suzuki S. Osteopontin expression in normal and hypobaric hypoxia-exposed rats. Acta Physiol (Oxf) 2008; 193:291-301. [PMID: 18284657 DOI: 10.1111/j.1748-1716.2008.01844.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Experimental pulmonary hypertension induced in a hypobaric hypoxic environment (HHE) is characterized by structural remodelling of the heart and pulmonary arteries. Osteopontin (OPN) has emerged as a key factor in cardiovascular remodelling in response to pressure or volume overload. We studied the possible effects of HHE on the OPN synthesis system. METHODS One hundred and forty-eight male Wistar rats were housed in a chamber with conditions equivalent of an altitude of 5500 m for up to 21 days. RESULTS Plasma OPN protein level was found to be significantly decreased on day 0.5 of exposure to HHE, as was the level in the adrenal gland (which secreted highest levels of OPN protein). In the right ventricle of the heart (mRNA) and the lung (protein), OPN expression was found to be significantly increased only on day 1 and day 5, respectively, of exposure to HHE. By immunohistochemistry, the distribution and intensity of OPN protein in several organs were found to alter during exposure to HHE. However, these changes in OPN synthesis did not coincide with the moderate increase in pulmonary arterial pressure (PAP) (maximal mean PAP, 24.5 mmHg) during HHE. CONCLUSION Pulmonary hypertension in HHE with conditions equivalent of an altitude of 5500 m may induce little or no OPN in heart and lung. Sustained induction may require a more severe PAP overload.
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Affiliation(s)
- M Uenoyama
- Division of Environmental Medicine, National Defense Medical College Research Institute, Tokorozawa, Japan
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7
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Harris GS, Lust RM, Katwa LC. Hemodynamic effects of chronic urotensin II administration in animals with and without aorto-caval fistula. Peptides 2007; 28:1483-9. [PMID: 17553596 PMCID: PMC2965601 DOI: 10.1016/j.peptides.2007.04.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 04/16/2007] [Accepted: 04/25/2007] [Indexed: 11/19/2022]
Abstract
Urotensin II (UTII) is a potent vasoactive peptide. Recent studies have demonstrated increased expression of both UTII and its receptor (UTR) expression in end-stage congestive heart failure (CHF), but it is unclear whether UTII and UTR are late stage markers of decompensation, or earlier adaptive responses. The purpose of this study was to measure the effects of chronic UTII administration in normal and volume overloaded animals. Chronic 4 weeks administration of UTII produced decreases in hemodynamic function in animals not subjected to volume overload while returning function to control levels in animals with overload. Expression levels of calcium regulatory proteins phospholamban (PLN), sarcoplasmic reticulum Ca(2+) ATPase (SERCA2), and Na(+)/Ca(2+) exchanger (NCX) were measured to determine if administration of UTII resulted in aberrant Ca(2+) handling. Changes in protein expression revealed that UTII influenced Ca(2+) handling proteins in normal animals although these changes are not seen in the volume overload.
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Affiliation(s)
| | | | - Laxmansa C. Katwa
- Correspondence and Reprints: Laxmansa C. Katwa, Ph.D., Department of Physiology, Rm. 6E-73C Brody Building, The Brody School of Medicine at East Carolina University, 600 Moye Blvd., Greenville, NC, 27834, U S A, Tel: (252) 744-1906, Fax: (252) 744-3460,
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Jiang X, Ren YP, Lv ZR. Ouabain induces cardiac remodeling in rats independent of blood pressure. Acta Pharmacol Sin 2007; 28:344-52. [PMID: 17302996 DOI: 10.1111/j.1745-7254.2007.00496.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To investigate the ouabain's effects on cardiac remodeling in rats. METHODS Male Sprague-Dawley rats were treated with ouabain. Systolic blood pressure (SBP) was recorded weekly. After 4 and 6 weeks, echocardiography were performed, hemodynamic parameters were measured by invasive cardiac catheterization, changes in cardiac ultrastructure were analyzed using transmission electron microscopy, the collagen fraction of the left ventricle was assessed with Picrosirius red stain, and RT-PCR was applied to evaluate the mRNA level of myosin heavy chain-alpha and -beta in the left ventricle. RESULTS Having been treated with ouabain for 4 weeks, there was no significant difference in the mean SBP of the two groups. However, left ventricular hypertrophy, myocardial ultrastructure deterioration, and extracellular matrix remodeling were induced by ouabain treatment; meanwhile, cardiac systolic and diastolic performance were both worsened. Moreover, the cardiac MHC-beta mRNA was upregulated by ouabain treatment, whereas MHC-alpha mRNA was downregulated. After 4 weeks, the mean SBP in the ouabain group began to increase and was significantly higher than that in control group after 6 weeks (P<0.01); the rats'cardiac structure and function were worsened. CONCLUSION These results suggested that ouabain induces alterations in cardiac structure and function, and the effects happened before the increase of blood pressure. The results indicated that ouabain induced cardiac remodeling in rats independent of blood pressure.
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Affiliation(s)
- Xing Jiang
- Geriatric-Cardiovascular Department, the People Hospital of Shaanxi Province and the Third Hospital of Xi'an Jiaotong University, Xi'an 710068, China.
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9
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Kanazawa F, Nakanishi K, Osada H, Kanamaru Y, Ohrui N, Uenoyama M, Masaki Y, Kanatani Y, Hiroi S, Tominaga S, Yakata-Suzuki A, Matsuyama S, Kawai T. Expression of endothelin-1 in the brain and lung of rats exposed to permanent hypobaric hypoxia. Brain Res 2005; 1036:145-54. [PMID: 15725412 DOI: 10.1016/j.brainres.2004.12.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 10/21/2004] [Accepted: 12/15/2004] [Indexed: 12/21/2022]
Abstract
High-altitude hypoxia causes pulmonary hypertension in humans and animals. Endothelin-1 (ET-1) is a novel and long-lasting vasoconstrictor. However, no study has dealt with the effects of a hypobaric hypoxic environment (HHE) on ET-1 activity in the brain. We examined 134 male rats permanently exposed to the equivalent of 5500 m altitude for 1 to 8 weeks. In these HHE rats, the mean pulmonary arterial pressure was significantly raised. The level of ET-1 protein, measured by enzyme immunoassay, increased rapidly in the lungs on exposure to HHE, but decreased in the brain. The level of ET-1 mRNA, measured by semiquantitative RT-PCR, was raised at 1, 4, and 6 weeks' exposure in the lungs and at 4 or more weeks' exposure in 3 of 8 brain regions. By in situ hybridization and immunohistochemistry of brain sections, ET-1 mRNA and protein were detected in the endothelial cells, neurons, and astrocyte-like cells in control rats. In HHE rats, the immunoreactive intensity for ET-1 protein decreased rapidly with time in these cells within the brain, although a few weakly ET-1 protein-positive cells were detected until 8 weeks' exposure to HHE. Only a few weakly ET-1 mRNA-positive endothelial cells were detected in any HHE rats. Although the reactivity for ET-1 mRNA had decreased significantly in neurons and astrocyte-like cells at 1 and 2 weeks' exposure to HHE, it was again strong in both types of cells at 4 weeks' exposure to HHE. These results raise the possibility that during exposure to HHE, ET-1 production in the lung may play a role in the development of pulmonary hypertension, while a decrease in ET-1 production within the brain may help to protect neurons by preventing or limiting the constriction of cerebral microvessels during the hypoxia induced by HHE.
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Affiliation(s)
- Fumiko Kanazawa
- Biochemical Section, 2nd Division, Aeromedical Laboratory, Japan Air Self-Defense Force, Tachikawa 190-0003, Japan
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10
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Letout A, Solares-Espinoza M, Mateo P, Koulmann N, Bahi L, Serrurier B, Favier R, Ventura-Clapier R, Bigard X. Adaptive changes in cardiac myosin heavy chain and creatine kinase isozymic profiles in rats native of altitude. ACTA ACUST UNITED AC 2005; 184:95-104. [PMID: 15916669 DOI: 10.1111/j.1365-201x.2005.01435.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM The developmental changes in the myosin heavy chain (MHC) profile, creatine kinase (CK) and lactate dehydrogenase (LDH) activities and isozyme expression occurring in heart were examined in rats born and living at altitude (La Paz, Bolivia, 3700 m, H(LP)) for 16 generations. We hypothesized that H(LP) rats respond differently to hypoxia than rats born and living at sea level, and secondarily exposed to altitude during 3 weeks (H(3W)). METHODS The cardiac expression of MHC, CK and LDH was studied in left (LV) and right ventricle (RV) of H(LP) animals 1, 2, 3, 4 and 18 weeks after birth, and compared with control normoxic (C groups) and H(3W) animals. RESULTS Rats secondarily exposed to hypoxia showed a lower alpha-MHC content than C or H(LP) rats in both LV and RV, 3 weeks after birth (P < 0.05), consistent with a delay in the maturation of the heart contractile phenotype. A global increase in the total CK activity was observed in the LV of H(3W) animals in comparison with C rats (P < 0.05), while no change was reported in H(LP) animals. In both ventricles, M-LDH activity was higher in H(3W) than in H(LP) and C rats (P < 0.05). The relative amount of alpha-MHC decreased by 20% in RV of 18-week-old H(LP) and H(3W) rats in comparison with C animals, consistent with the hypoxia-induced ventricular enlargement (P < 0.01). An increased activity of the foetal B-CK subunit was observed in both LV and RV of H(3W) rats in comparison with H(LP) and C animals (P < 0.05). CONCLUSION This study demonstrates that rats native and living at altitude for several generations present some features relevant to genetic selection to altitude.
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Affiliation(s)
- A Letout
- Centre de Recherches du Service de Santé des Armées, La Tronche Cedex, France
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11
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Cueille C, Birot O, Bigard X, Hagner S, Garel JM. Post-transcriptional regulation of CRLR expression during hypoxia. Biochem Biophys Res Commun 2005; 326:23-9. [PMID: 15567147 DOI: 10.1016/j.bbrc.2004.10.205] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Indexed: 11/21/2022]
Abstract
Adrenomedullin and CGRP are two potent vasodilator peptides, and their receptors are formed by heterodimerization of the CRLR and a RAMP molecule. Hypoxia is associated with many diseases of the cardiovascular system. It was recently shown that the human CRLR gene promoter contains an HIF-1alpha regulatory element, and that CRLR mRNA was increased by hypoxia in human endothelial cells. In the present work, we have assessed the effect of hypoxia on CRLR expression both in vivo and in vitro using two different experimental models. We have also investigated the effect of hypoxia on RAMP expression. (1) We analyzed the effects of a chronic hypobaric hypoxia on rat ventricle expression of RAMPs and CRLR. (2) Acute hypoxia was studied in human vascular smooth cells from coronary artery (CASMC) exposed for 6h to 2% O(2). RT-PCR was used to analyze the mRNA expression, and protein levels were determined by Western blotting. A sharp increase in HIF-1alpha protein levels was induced by hypoxia in CASMC, and 3.5-fold rise of the CRLR protein occurred after 1h of hypoxia in face of unchanged mRNA levels. The CRLR mRNA levels were only elevated later. A clear decrease of the CRLR protein level occurred after 3 and 6h of hypoxia. Thus, acute hypoxia in CASMC induced a rapid change of the CRLR protein amount independently of changes in the CRLR mRNA. This finding suggested a major post-transcriptional effect of hypoxia on CRLR expression in CASMC. RAMP2 and adrenomedullin mRNAs were increased after 4h, but no change was observed for RAMP1. Chronic hypoxia in rats enhanced both mRNA and protein levels of the three RAMPs and CRLR in right and left ventricles. Together, our in vivo and in vitro data suggested that hypoxia up-regulates both adrenomedullin and its receptor (CRLR/RAMP2) to enhance the signaling at the target cell.
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Affiliation(s)
- Carine Cueille
- INSERM U-606, Hôpital Lariboisière, 75475 Paris-Cedex 10, France
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Nakanishi K, Osada H, Uenoyama M, Kanazawa F, Ohrui N, Masaki Y, Hayashi T, Kanatani Y, Ikeda T, Kawai T. Expressions of adrenomedullin mRNA and protein in rats with hypobaric hypoxia-induced pulmonary hypertension. Am J Physiol Heart Circ Physiol 2004; 286:H2159-68. [PMID: 14715505 DOI: 10.1152/ajpheart.00846.2003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experimental pulmonary hypertension induced in a hypobaric hypoxic environment (HHE) is characterized by structural remodeling of the heart and pulmonary arteries. Adrenomedullin (AM) has diuretic, natriuretic, and hypotensive effects. To study the possible effects of HHE on the AM synthesis system, 150 male Wistar rats were housed in a chamber at the equivalent of a 5,500-m altitude level for 21 days. After 14 days of exposure to HHE, pulmonary arterial pressure (PAP) was significantly increased (compared with control rats). The plasma AM protein level was significantly increased on day 21 of exposure to HHE. In the right ventricle (RV), right atrium, and left atrium of the heart, the expressions of AM mRNA and protein were increased in the middle to late phase (5–21 days) of HHE, whereas in the brain and lung they were increased much earlier (0.5–5 days). In situ hybridization and immunohistochemistry showed AM mRNA and protein staining to be more intense in the RV in animals in the middle to late phase of HHE exposure than in the controls. During HHE, these changes in AM synthesis, which occurred strongly in the RV, occurred alongside the increase in PAP. Conceivably, AM may play a role in modulating pulmonary hypertension in HHE.
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Affiliation(s)
- Kuniaki Nakanishi
- Department of Pathology, National Defense Medical College, Tokorozawa 359-8513, Japan.
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Sharma S, Taegtmeyer H, Adrogue J, Razeghi P, Sen S, Ngumbela K, Essop MF. Dynamic changes of gene expression in hypoxia-induced right ventricular hypertrophy. Am J Physiol Heart Circ Physiol 2003; 286:H1185-92. [PMID: 14630626 DOI: 10.1152/ajpheart.00916.2003] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypobaric hypoxia induces right ventricular hypertrophy. The relative contribution of pulmonary hypertension, decreased arterial oxygen, and neuroendocrine stimulation to the transcriptional profile of hypoxia-induced right ventricular hypertrophy is unknown. Whereas both ventricles are exposed to hypoxia and neuroendocrine stimulation, only the right ventricle is exposed to increased load. We postulated that right ventricular hypertrophy would reactivate the fetal gene transcriptional profile in response to increased load. We measured the expression of candidate genes in the right ventricle of rats exposed to hypobaric hypoxia (11% O(2)) and compared the results with the left ventricle. Hypoxia induced right ventricular hypertrophy without fibrosis. In the right ventricle only, atrial natriuretic factor transcript levels progressively increased starting at day 7. Metabolic genes were differentially regulated, suggesting a substrate switch from fatty acids to glucose during early hypoxia and a switch back to fatty acids by day 14. There was also a switch in myosin isogene expression and a downregulation of sarcoplasmic/endoplasmic ATPase 2a during early hypoxia, whereas later, both myosin isoforms and SERCA2a were upregulated. When the right and left ventricle were compared, the transcript levels of all genes, except for myosin isoforms and pyruvate dehydrogenase kinase-4, differed dramatically suggesting that all these genes are regulated by load. Our findings demonstrate that hypoxia-induced right ventricular hypertrophy transiently reactivates the fetal gene program. Furthermore, myosin iso-gene and pyruvate dehydrogenase kinase-4 expression is not affected by load, suggesting that either hypoxia itself or neuroendocrine stimulation is the primary regulator of these genes.
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Affiliation(s)
- Saumya Sharma
- Dept. of Internal Medicine, Division of Cardiology, Univ. of Texas-Houston Medical School, 6431 Fannin, MSB 1.246, Houston, TX 77030, USA
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