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Kumar R, Vitvitsky V, Sethaudom A, Singhal R, Solanki S, Alibeckoff S, Hiraki HL, Bell HN, Andren A, Baker BM, Lyssiotis CA, Shah YM, Banerjee R. Sulfide oxidation promotes hypoxic angiogenesis and neovascularization. Nat Chem Biol 2024:10.1038/s41589-024-01583-8. [PMID: 38509349 DOI: 10.1038/s41589-024-01583-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 02/20/2024] [Indexed: 03/22/2024]
Abstract
Angiogenic programming in the vascular endothelium is a tightly regulated process for maintaining tissue homeostasis and is activated in tissue injury and the tumor microenvironment. The metabolic basis of how gas signaling molecules regulate angiogenesis is elusive. Here, we report that hypoxic upregulation of ·NO in endothelial cells reprograms the transsulfuration pathway to increase biogenesis of hydrogen sulfide (H2S), a proangiogenic metabolite. However, decreased H2S oxidation due to sulfide quinone oxidoreductase (SQOR) deficiency synergizes with hypoxia, inducing a reductive shift and limiting endothelial proliferation that is attenuated by dissipation of the mitochondrial NADH pool. Tumor xenografts in whole-body (WBCreSqorfl/fl) and endothelial-specific (VE-cadherinCre-ERT2Sqorfl/fl) Sqor-knockout mice exhibit lower mass and angiogenesis than control mice. WBCreSqorfl/fl mice also exhibit decreased muscle angiogenesis following femoral artery ligation compared to control mice. Collectively, our data reveal the molecular intersections between H2S, O2 and ·NO metabolism and identify SQOR inhibition as a metabolic vulnerability for endothelial cell proliferation and neovascularization.
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Affiliation(s)
- Roshan Kumar
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Victor Vitvitsky
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Apichaya Sethaudom
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Rashi Singhal
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Sumeet Solanki
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Sydney Alibeckoff
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Harrison L Hiraki
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Hannah N Bell
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Anthony Andren
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Brendon M Baker
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Costas A Lyssiotis
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Yatrik M Shah
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA.
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Sharma P, Sri Swetha Victoria V, Praneeth Kumar P, Karmakar S, Swetha M, Reddy A. Cross-talk between insulin resistance and nitrogen species in hypoxia leads to deterioration of tissue and homeostasis. Int Immunopharmacol 2023; 122:110472. [PMID: 37392570 DOI: 10.1016/j.intimp.2023.110472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 05/19/2023] [Accepted: 06/07/2023] [Indexed: 07/03/2023]
Abstract
Hypoxia has been linked with insulin resistance as it produces changes in the metabolism of the cell; in which the adipocytes impede the insulin receptor tyrosine, phosphorylation, directing at decreased levels of transport of glucose. At this juncture, we are focusing on cross-talk between insulin resistance and nitrogen species in hypoxia, leading to the deterioration of tissue and homeostasis. Physiological levels of nitric oxide play a very crucial role in acting as a priority effector and signaling molecule, arbitrating the body's responses to hypoxia. Both ROS and RNS are associated with a reduction in IRS1 phosphorylation in tyrosine, which leads to reduced levels of IRS1 content and insulin response, which further leads to insulin resistance. Cellular hypoxia is a trigger to inflammatory mediators which signal tissue impairment and initiate survival requirements. But, hypoxia-mediated inflammation act as a protective role by an immune response and promotes wound healing during infection. In this review, we abridge the crosstalk between the inflammation and highlight the dysregulation in physiological consequences due to diabetes mellitus. Finally, we review various treatments available for its related physiological complications.
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Affiliation(s)
- Priyanshy Sharma
- Animal Cell Culture Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nādu, India
| | - V Sri Swetha Victoria
- Animal Cell Culture Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nādu, India
| | - P Praneeth Kumar
- Animal Cell Culture Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nādu, India
| | - Sarbani Karmakar
- Animal Cell Culture Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nādu, India
| | - Mudduluru Swetha
- Animal Cell Culture Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nādu, India
| | - Amala Reddy
- Animal Cell Culture Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nādu, India.
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Kumar R, Vitvitsky V, Seth P, Hiraki HL, Bell H, Andren A, Singhal R, Baker BM, Lyssiotis CA, Shah YM, Banerjee R. Sulfide oxidation promotes hypoxic angiogenesis and neovascularization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532677. [PMID: 36993187 PMCID: PMC10055101 DOI: 10.1101/2023.03.14.532677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Angiogenic programming in the vascular endothelium is a tightly regulated process to maintain tissue homeostasis and is activated in tissue injury and the tumor microenvironment. The metabolic basis of how gas signaling molecules regulate angiogenesis is elusive. Herein, we report that hypoxic upregulation of NO synthesis in endothelial cells reprograms the transsulfuration pathway and increases H 2 S biogenesis. Furthermore, H 2 S oxidation by mitochondrial sulfide quinone oxidoreductase (SQOR) rather than downstream persulfides, synergizes with hypoxia to induce a reductive shift, limiting endothelial cell proliferation that is attenuated by dissipation of the mitochondrial NADH pool. Tumor xenografts in whole-body WB Cre SQOR fl/fl knockout mice exhibit lower mass and reduced angiogenesis compared to SQOR fl/fl controls. WB Cre SQOR fl/fl mice also exhibit reduced muscle angiogenesis following femoral artery ligation, compared to controls. Collectively, our data reveal the molecular intersections between H 2 S, O 2 and NO metabolism and identify SQOR inhibition as a metabolic vulnerability for endothelial cell proliferation and neovascularization. Highlights Hypoxic induction of •NO in endothelial cells inhibits CBS and switches CTH reaction specificity Hypoxic interruption of the canonical transsulfuration pathway promotes H 2 S synthesis Synergizing with hypoxia, SQOR deficiency induces a reductive shift in the ETC and restricts proliferationSQOR KO mice exhibit lower neovascularization in tumor xenograft and hind limb ischemia models.
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4
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Vega-Tapia F, Peñaloza E, Krause BJ. Specific arterio-venous transcriptomic and ncRNA-RNA interactions in human umbilical endothelial cells: A meta-analysis. iScience 2021; 24:102675. [PMID: 34222842 PMCID: PMC8243012 DOI: 10.1016/j.isci.2021.102675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/21/2021] [Accepted: 05/27/2021] [Indexed: 01/06/2023] Open
Abstract
Whether arterial-venous differences of primary endothelial cells commonly used for vascular research are preserved in vitro remains under debate. To address this issue, a meta-analysis of Affymetrix transcriptomic data sets from human umbilical artery (HUAECs) and vein (HUVEC) endothelial cells was performed. The meta-analysis showed 2,742 transcripts differentially expressed (false discovery rate <0.05), of which 78% were downregulated in HUVECs. Comparisons with RNA-seq data sets showed high levels of agreement and correlation (p < 0.0001), identifying 84 arterial-venous identity markers. Functional analysis revealed enrichment of key vascular processes in HUAECs/HUVECs, including nitric oxide- (NO) and hypoxia-related genes, as well as differences in miRNA- and ncRNA-mRNA interaction profiles. A proof of concept of these findings in primary cells exposed to hypoxia in vitro and in vivo confirmed the arterial-venous differences in NO-related genes and miRNAs. Altogether, these data defined a cross-platform arterial-venous transcript profile for cultured HUAEC-HUVEC and support a preserved identity involving key vascular pathways post-transcriptionally regulated in vitro. Transcriptional differences among HUAEC and HUVEC are preserved in culture These differences occur even after correcting for experimental conditions The heterogenous regulation affects NO- and hypoxia-related genes Cell-specific ncRNA/mRNA interactions are found
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Affiliation(s)
- Fabian Vega-Tapia
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Avenida Libertador Bernardo O'Higgins 611, Rancagua, Chile
| | - Estefania Peñaloza
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Avenida Libertador Bernardo O'Higgins 611, Rancagua, Chile
| | - Bernardo J Krause
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Avenida Libertador Bernardo O'Higgins 611, Rancagua, Chile
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Oxidative stress and immune cell activation quantification in sepsis and non-sepsis critical care patients by neopterin/7,8-dihydroneopterin analysis. Pteridines 2020. [DOI: 10.1515/pteridines-2020-0015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Abstract
Introduction: Neopterin and 7,8-dihydroneopterin are used as biomarkers of oxidative stress and inflammation, but the effect of kidney function on these measurements has not been extensively explored. We examine the levels of oxidative stress, inflammation and kidney function in intensive patients and compare them to equivalent patients without sepsis.
Methods: 34 Intensive care patients were selected for the study, 14 without sepsis and 20 with. Both groups had equivalent levels of trauma, assessed by SAPS II, SOFA, and APACHE II and III scores. Plasma and urinary neopterin and total neopterin (neopterin + 7,8-dihydroneopterin) values were measured.
Results: Neopterin and total neopterin were significantly elevated in urine and plasma for multiple days in sepsis versus non-sepsis patients. Plasma neopterin and total neopterin have decreasing relationships with increased eGFR (p<0.008 and p<0.001, respectively). Plasma/urinary neopterin and total neopterin ratios demonstrate that total neopterin flux is more influenced by eGFR than neopterin, with significantce of p<0.02 and p<0.0002 respectively.
Conclusion: Sepsis patients present with greater levels of oxidative stress and immune system activation than non-sepsis patients of equal levels of trauma, as measured by neopterin and total neopterin. eGFR may need to be taken into account when accessing the level of inflammation from urinary neopterin measurements.
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Hannemann J, Zummack J, Hillig J, Böger R. Metabolism of asymmetric dimethylarginine in hypoxia: from bench to bedside. Pulm Circ 2020; 10:2045894020918846. [PMID: 32313644 PMCID: PMC7158260 DOI: 10.1177/2045894020918846] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 03/20/2020] [Indexed: 12/16/2022] Open
Abstract
Acute hypoxia and chronic hypoxia induce pulmonary vasoconstriction. While hypoxic pulmonary vasoconstriction is a physiological response if parts of the lung are affected, global exposure to hypoxic conditions may lead to clinical conditions like high-altitude pulmonary hypertension. Nitric oxide is the major vasodilator released from the vascular endothelium. Nitric oxide-dependent vasodilation is impaired in hypoxic conditions. Inhibition of nitric oxide synthesis is the most rapid and easily reversible molecular mechanism to regulate nitric oxide-dependent vascular function in response to physiological and pathophysiological stimuli. Asymmetric dimethylarginine is an endogenous, competitive inhibitor of nitric oxide synthase and a risk marker for major cardiovascular events and mortality. Elevated asymmetric dimethylarginine has been observed in animal models of hypoxia as well as in human cohorts under chronic and chronic intermittent hypoxia at high altitude. In lowlanders, asymmetric dimethylarginine is high in patients with pulmonary hypertension. We have recently shown that high asymmetric dimethylarginine at sea level is a predictor for high-altitude pulmonary hypertension. Asymmetric dimethylarginine is a highly regulated molecule, both by its biosynthesis and metabolism. Methylation of L-arginine by protein arginine methyltransferases was shown to be increased in hypoxia. Furthermore, the metabolism of asymmetric dimethylarginine by dimethylarginine dimethylaminohydrolases (DDAH1 and DDAH2) is decreased in animal models of hypoxia. Whether these changes are caused by transcriptional or posttranslational modifications remains to be elucidated. Current data suggest a major role of asymmetric dimethylarginine in regulating pulmonary arterial nitric oxide production in hypoxia. Further studies are needed to decipher the molecular mechanisms regulating asymmetric dimethylarginine in hypoxia and to understand their clinical significance.
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Affiliation(s)
- Juliane Hannemann
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany
| | - Julia Zummack
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany
| | - Jonas Hillig
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany
| | - Rainer Böger
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany
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7
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Passive smoking acutely affects the microcirculation in healthy non-smokers. Microvasc Res 2020; 128:103932. [DOI: 10.1016/j.mvr.2019.103932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/31/2019] [Accepted: 09/26/2019] [Indexed: 02/02/2023]
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Yoon G, Oh CS, Kim HS. Distinctive expression patterns of hypoxia-inducible factor-1α and endothelial nitric oxide synthase following hypergravity exposure. Oncotarget 2018; 7:33675-88. [PMID: 27191892 PMCID: PMC5085111 DOI: 10.18632/oncotarget.9372] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/05/2016] [Indexed: 01/13/2023] Open
Abstract
This study was designed to examine the expression of hypoxia-inducible factor-1α (HIF-1α) and the level and activity of endothelial nitric oxide synthase (eNOS) in the hearts and livers of mice exposed to hypergravity. Hypergravity-induced hypoxia and the subsequent post-exposure reoxygenation significantly increased cardiac HIF-1α levels. Furthermore, the levels and activity of cardiac eNOS also showed significant increase immediately following hypergravity exposure and during the reoxygenation period. In contrast, the expression of phosphorylated Akt (p-Akt) and phosphorylated extracellular signal-regulated kinase (p-ERK) showed significant elevation only during the reoxygenation period. These data raise the possibility that the increase in cardiac HIF-1α expression induced by reoxygenation involves a cascade of signaling events, including activation of the Akt and ERK pathways. In the liver, HIF-1α expression was significantly increased immediately after hypergravity exposure, indicating that hypergravity exposure to causes hepatocellular hypoxia. The hypergravity-exposed livers showed significantly higher eNOS immunoreactivity than did those of control mice. Consistent with these results, significant increases in eNOS activity and nitrate/nitrite levels were also observed. These findings suggest that hypergravity-induced hypoxia plays a significant role in the upregulation of hepatic eNOS.
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Affiliation(s)
- Gun Yoon
- Department of Obstetrics and Gynecology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Choong Sik Oh
- Aerospace Medicine Research Center, Republic of Korea Air Force Aerospace Medical Center, Cheongju-si, Chungcheongbuk-do, Republic of Korea
| | - Hyun-Soo Kim
- Department of Pathology, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
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McLay KM, Fontana FY, Nederveen JP, Paterson DH, Pogliaghi S, Murias JM. Response to Letter from Tremblay & King: Near-infrared spectroscopy: can it measure conduit artery endothelial function? Exp Physiol 2016; 102:128-129. [DOI: 10.1113/ep085909] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kaitlin M. McLay
- Canadian Centre for Activity and Aging; The University of Western Ontario; London ON Canada
- School of Kinesiology; The University of Western Ontario; London ON Canada
| | - Federico Y. Fontana
- Department of Neurosciences; Biomedicine and Movement Sciences; University of Verona; Verona Italy
| | - Josh P. Nederveen
- Canadian Centre for Activity and Aging; The University of Western Ontario; London ON Canada
- School of Kinesiology; The University of Western Ontario; London ON Canada
| | - Donald H. Paterson
- Canadian Centre for Activity and Aging; The University of Western Ontario; London ON Canada
- School of Kinesiology; The University of Western Ontario; London ON Canada
| | - Silvia Pogliaghi
- Department of Neurosciences; Biomedicine and Movement Sciences; University of Verona; Verona Italy
| | - Juan M. Murias
- Canadian Centre for Activity and Aging; The University of Western Ontario; London ON Canada
- School of Kinesiology; The University of Western Ontario; London ON Canada
- Faculty of Kinesiology; University of Calgary; Calgary AB Canada
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Paik JY, Jung KH, Lee JH, Park JW, Lee KH. Reactive oxygen species-driven HIF1α triggers accelerated glycolysis in endothelial cells exposed to low oxygen tension. Nucl Med Biol 2016; 45:8-14. [PMID: 27835826 DOI: 10.1016/j.nucmedbio.2016.10.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 10/12/2016] [Accepted: 10/24/2016] [Indexed: 12/26/2022]
Abstract
Endothelial cells and their metabolic state regulate glucose transport into underlying tissues. Here, we show that low oxygen tension stimulates human umbilical vein endothelial cell 18F-fluorodeoxyglucose (18F-FDG) uptake and lactate production. This was accompanied by augmented hexokinase activity and membrane Glut-1, and increased accumulation of hypoxia-inducible factor-1α (HIF1α). Restoration of oxygen reversed the metabolic effect, but this was blocked by HIF1α stabilization. Hypoxia-stimulated 18F-FDG uptake was completely abrogated by silencing of HIF1α expression or by a specific inhibitor. There was a rapid and marked increase of reactive oxygen species (ROS) by hypoxia, and ROS scavenging or NADPH oxidase inhibition completely abolished hypoxia-stimulated HIF1α and 18F-FDG accumulation, placing ROS production upstream of HIF1α signaling. Hypoxia-stimulated HIF1α and 18F-FDG accumulation was blocked by the protein kinase C (PKC) inhibitor, staurosporine. The phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin, blocked hypoxia-stimulated 18F-FDG uptake and attenuated hypoxia-responsive element binding of HIF1α without influencing its accumulation. Thus, ROS-driven HIF1α accumulation, along with PKC and PI3K signaling, play a key role in triggering accelerated glycolysis in endothelial cells under hypoxia, thereby contributing to 18F-FDG transport.
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Affiliation(s)
- Jin-Young Paik
- Department of Nuclear Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Kyung-Ho Jung
- Department of Nuclear Medicine, Samsung Medical Center, Seoul, Republic of Korea; Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jin-Hee Lee
- Department of Nuclear Medicine, Samsung Medical Center, Seoul, Republic of Korea; Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jin-Won Park
- Department of Nuclear Medicine, Samsung Medical Center, Seoul, Republic of Korea; Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Kyung-Han Lee
- Department of Nuclear Medicine, Samsung Medical Center, Seoul, Republic of Korea; Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
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Zinck T, Illum R, Jansen-Olesen I. Increased Expression of Endothelial and Neuronal Nitric Oxide Synthase In Dura and Pia Mater After Air Stress. Cephalalgia 2016; 26:14-25. [PMID: 16396662 DOI: 10.1111/j.1468-2982.2005.00978.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Stress is the leading precipitating factor for migraine attacks but the underlying mechanism is currently unknown. Nitric oxide (NO) has been implicated in migraine pathogenesis based on the ability of NO donors to induce migraine attacks. In the present study, we investigated in Wistar rats the effect of air stress on nitric oxide synthase (NOS) mRNA and protein expression in dura and pia mater using real-time polymerase chain reaction and Western blotting, respectively. Endothelial (e)NOS protein expression was significantly increased in dura and pia mater after air stress. Significantly augmented neuronal (n)NOS protein expression was detected in pia mater after air stress but not in dura mater. Inducible NOS mRNA and protein expression levels in dura and pia mater were unaffected by stress. The increased expression of eNOS in dura mater and eNOS and nNOS in pia mater seen after stress could not be antagonized by treatment with the migraine drug sumatriptan. These findings point towards the involvement of increased NO concentrations in dura and pia mater in response to air stress. However, the role of these findings in relation to migraine pathophysiology remains unclear.
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Affiliation(s)
- T Zinck
- Department of Pharmacology, The Danish University of Pharmaceutical Sciences, Copenhagen, Denmark
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12
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Chalupsky K, Kračun D, Kanchev I, Bertram K, Görlach A. Folic Acid Promotes Recycling of Tetrahydrobiopterin and Protects Against Hypoxia-Induced Pulmonary Hypertension by Recoupling Endothelial Nitric Oxide Synthase. Antioxid Redox Signal 2015; 23:1076-91. [PMID: 26414244 PMCID: PMC4657514 DOI: 10.1089/ars.2015.6329] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 09/21/2015] [Accepted: 09/21/2015] [Indexed: 01/29/2023]
Abstract
AIMS Nitric oxide (NO) derived from endothelial NO synthase (eNOS) has been implicated in the adaptive response to hypoxia. An imbalance between 5,6,7,8-tetrahydrobiopterin (BH4) and 7,8-dihydrobiopterin (BH2) can result in eNOS uncoupling and the generation of superoxide instead of NO. Dihydrofolate reductase (DHFR) can recycle BH2 to BH4, leading to eNOS recoupling. However, the role of DHFR and eNOS recoupling in the response to hypoxia is not well understood. We hypothesized that increasing the capacity to recycle BH4 from BH2 would improve NO bioavailability as well as pulmonary vascular remodeling (PVR) and right ventricular hypertrophy (RVH) as indicators of pulmonary hypertension (PH) under hypoxic conditions. RESULTS In human pulmonary artery endothelial cells and murine pulmonary arteries exposed to hypoxia, eNOS was uncoupled as indicated by reduced superoxide production in the presence of the nitric oxide synthase inhibitor, L-(G)-nitro-L-arginine methyl ester (L-NAME). Concomitantly, NO levels, BH4 availability, and expression of DHFR were diminished under hypoxia. Application of folic acid (FA) restored DHFR levels, NO bioavailability, and BH4 levels under hypoxia. Importantly, FA prevented the development of hypoxia-induced PVR, right ventricular pressure increase, and RVH. INNOVATION FA-induced upregulation of DHFR recouples eNOS under hypoxia by improving BH4 recycling, thus preventing hypoxia-induced PH. CONCLUSION FA might serve as a novel therapeutic option combating PH.
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Affiliation(s)
- Karel Chalupsky
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Damir Kračun
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Ivan Kanchev
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Katharina Bertram
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Agnes Görlach
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
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14
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Li H, Liu T, Chen W, Jain MR, Vatner DE, Vatner SF, Kudej RK, Yan L. Proteomic mechanisms of cardioprotection during mammalian hibernation in woodchucks, Marmota monax. J Proteome Res 2013; 12:4221-9. [PMID: 23855383 DOI: 10.1021/pr400580f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mammalian hibernation is a unique strategy for winter survival in response to limited food supply and harsh climate, which includes resistance to cardiac arrhythmias. We previously found that hibernating woodchucks (Marmota monax) exhibit natural resistance to Ca2+ overload-related cardiac dysfunction and nitric oxide (NO)-dependent vasodilation, which maintains myocardial blood flow during hibernation. Since the cellular/molecular mechanisms mediating the protection are less clear, the goal of this study was to investigate changes in the heart proteome and reveal related signaling networks that are involved in establishing cardioprotection in woodchucks during hibernation. This was accomplished using isobaric tags for a relative and absolute quantification (iTRAQ) approach. The most significant changes observed in winter hibernation compared to summer non-hibernation animals were upregulation of the antioxidant catalase and inhibition of endoplasmic reticulum (ER) stress response by downregulation of GRP78, mechanisms which could be responsible for the adaptation and protection in hibernating animals. Furthermore, protein networks pertaining to NO signaling, acute phase response, CREB and NFAT transcriptional regulations, protein kinase A and α-adrenergic signaling were also dramatically upregulated during hibernation. These adaptive mechanisms in hibernators may provide new directions to protect myocardium of non-hibernating animals, especially humans, from cardiac dysfunction induced by hypothermic stress and myocardial ischemia.
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Affiliation(s)
- Hong Li
- Center for Advanced Proteomics Research and Department of Biochemistry and Molecular Biology, Rutgers University-New Jersey Medical School Cancer Center, Newark, New Jersey 07103, United States.
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15
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Fraisl P. Crosstalk between oxygen- and nitric oxide-dependent signaling pathways in angiogenesis. Exp Cell Res 2013; 319:1331-9. [PMID: 23485765 DOI: 10.1016/j.yexcr.2013.02.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 01/08/2023]
Abstract
With every heart beat blood rushes through a complex network of tubes to deliver essential ingredients of life, oxygen and nutrients. Consequently, this network of blood vessels is an indispensable part of vertebrate physiology. Its organization and architecture is highly dynamic in its form and function. Understanding how blood vessels develop, a process referred to as angiogenesis, is equally important as to know how they function considering that failure or misalignment of this process results in disorder and disease, in many cases of which death is inevitable. Much has been learned about the angiogenic process and the critical contributors of blood vessel function. A central determinant is oxygen, an evident contributor given the fact that oxygen delivery is a primary feature of blood vessel function. Not only is oxygen however essential for mitochondrial energy production, it also serves as a key molecule in various biochemical reactions, such as the formation of nitric oxide (NO), on its part a critical regulator of vascular tone and vessel homeostasis. Hence, oxygen abundance relates to the production of NO, and NO in turn regulates oxygen delivery and consumption. Given the importance of the intrinsic link these two molecules exert on angiogenesis and vessel function; this review shall highlight our current understanding on how these two molecules cooperate to form blood vessels.
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Affiliation(s)
- Peter Fraisl
- Cell Metabolism and Proliferation Laboratory, Vesalius Research Center (VRC), VIB, 3000 Leuven, Belgium.
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Ho JJD, Man HSJ, Marsden PA. Nitric oxide signaling in hypoxia. J Mol Med (Berl) 2012; 90:217-31. [DOI: 10.1007/s00109-012-0880-5] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/03/2012] [Accepted: 02/06/2012] [Indexed: 01/06/2023]
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Zong F, Zuo XR, Wang Q, Zhang SJ, Xie WP, Wang H. Iptakalim rescues human pulmonary artery endothelial cells from hypoxia-induced nitric oxide system dysfunction. Exp Ther Med 2011; 3:535-539. [PMID: 22969925 DOI: 10.3892/etm.2011.414] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 11/22/2011] [Indexed: 11/06/2022] Open
Abstract
The aim of this study was to assess whether hypoxia inhibits endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) production, and whether iptakalim may rescue human pulmonary artery endothelial cells (HPAECs) from hypoxia-induced NO system dysfunction. HPAECs were cultured under hypoxic conditions in the absence or presence of 0.1, 10 and 1,000 μM iptakalim or the combination of 10 μM iptakalim and 1, 10 and 100 μM glibenclamide for 24 h, and the eNOS activity and NO levels were measured in the conditioned medium from the HPAEC cultures. The eNOS activity and NO levels were reduced significantly in the conditioned medium from HPAEC cultures under hypoxic conditions. Pre-treatment with 10 μM iptakalim normalized the reduction of the eNOS activity and NO levels caused by hypoxia in the conditioned medium from HPAEC cultures. Iptakalim raised the eNOS activity and NO levels under hypoxic conditions, but was blocked by the K(ATP) channel blocker, glibenclamide. Our results indicate that hypoxia impairs NO system function, whereas the ATP-sensitive K(+) channel opener, iptakalim, may rescue HPAECs from hypoxia-induced NO system dysfunction.
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Ducsay CA, Myers DA. eNOS activation and NO function: differential control of steroidogenesis by nitric oxide and its adaptation with hypoxia. J Endocrinol 2011; 210:259-69. [PMID: 21653733 DOI: 10.1530/joe-11-0034] [Citation(s) in RCA: 40] [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: 02/06/2023]
Abstract
Nitric oxide (NO) plays a role in a wide range of physiological processes. Aside from its widely studied function in the regulation of vascular function, NO has been shown to impact steroidogenesis in a number of different tissues. The goal of this review is to explore the effects of NO on steroid production and further, to discern its source(s) and mechanism of action. Attention will be given to the regulation of NO synthases in specific endocrine tissues including ovaries, testes, and adrenal glands. The effects of hypoxia on generation of NO and subsequent effects on steroid biosynthesis will also be examined. Finally, a potential model for the interaction of hypoxia on NO synthesis and steroid production is proposed.
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Affiliation(s)
- Charles A Ducsay
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
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Vladimirov YA, Proskurnina EV. Free radicals and cell chemiluminescence. BIOCHEMISTRY (MOSCOW) 2010; 74:1545-66. [DOI: 10.1134/s0006297909130082] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Ostergaard L, Simonsen U, Eskildsen-Helmond Y, Vorum H, Uldbjerg N, Honoré B, Mulvany MJ. Proteomics reveals lowering oxygen alters cytoskeletal and endoplasmatic stress proteins in human endothelial cells. Proteomics 2009; 9:4457-67. [PMID: 19670369 DOI: 10.1002/pmic.200800130] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A proteomic approach was applied to explore the signalling pathways elicited by lowering O(2) in endothelial cells. Endothelial cells isolated from native umbilical cords were subjected to 21, 5, or 1% O(2) for 24 h. 2-D PAGE was performed and candidate proteins were identified using LC-MS/MS. Lowering of O(2) from 21 to 5% induced upregulation of cofilin-1, cyclophilin A, tubulin and tubulin fragments, a fragment of glucose-regulated protein 78 (Grp78) and calmodulin. The upregulation of Grp78 suggested that ER stress proteins were altered and indeed Grp94 and caspase 12 expression were increased in cells exposed to 5% O(2). The presence of ER stress is also supported by findings of blunted caffeine-evoked ER calcium release in cells exposed to 5 and 1% O(2). Exposure to 1% O(2) caused increases in cofilin-1, cyclophilin A, and caspase 12 as well as a decrease of beta-actin, but it did not alter the expression of calmodulin, tubulin, Grp78, and Grp94. Incubation with CoCl(2), a stabilizer of the hypoxia-inducible factor, increased the expression of several of the proteins. The present investigations reveal that lowering O(2), probably in part through hypoxia-inducible factor, alter the expression of a series of proteins mainly involved in cytoskeletal changes (e.g. cofilin-1, tubulin, and beta-actin) and in ER stress/apoptosis (e.g. Grp78/94, caspase 12, and cyclophilin A).
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Affiliation(s)
- Louise Ostergaard
- Department of Pharmacology, University of Aarhus, 8000 Aarhus C, Denmark
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Monau TR, Vargas VE, King N, Yellon SM, Myers DA, Ducsay CA. Long-term hypoxia increases endothelial nitric oxide synthase expression in the ovine fetal adrenal. Reprod Sci 2009; 16:865-74. [PMID: 19525401 DOI: 10.1177/1933719109336678] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study was designed to test the hypothesis that fetal adrenal nitric oxide synthase (NOS) is elevated in response to long-term hypoxia (LTH). Pregnant ewes were maintained at high altitude (3820 m) for approximately the last 100 days of gestation. Between days 138 and 141 of gestation, adrenal glands were collected from LTH fetuses and age-matched normoxic controls. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western analysis were used to quantify NOS expression, and NOS distribution was examined by immunohistochemistry and double-staining immunofluorescence for endothelial NOS (eNOS) and 17alpha-hydroxylase (CYP17). Neuronal NOS (nNOS) was expressed at very low levels and with no differences between groups. Expression of eNOS was significantly greater in the LTH group compared with control. Neuronal NOS was distributed throughout the cortex while the greatest density of eNOS was observed in the zona fasciculata/reticularis area and eNOS co-localized with CYP17. We conclude that LTH enhances eNOS expression in the inner adrenal cortex which may play a role in regulation of cortisol biosynthesis in the LTH fetus.
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Affiliation(s)
- Tshepo R Monau
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California 92350, USA
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Hypoxia-induced regulation of nitric oxide synthase in cardiac endothelial cells and myocytes and the role of the PI3-K/PKB pathway. Mol Cell Biochem 2008; 321:23-35. [PMID: 18791856 DOI: 10.1007/s11010-008-9906-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 08/19/2008] [Indexed: 01/26/2023]
Abstract
UNLABELLED The roles of endothelial nitric oxide synthase (eNOS), and its putative association with protein kinase B (PKB), and inducible nitric oxide synthase (iNOS) are not well characterized in hypoxic cardiac cells and there is a lack of studies that measure nitric oxide (NO) directly. OBJECTIVE To measure NO production in cardiomyocytes and cardiac microvascular endothelial cells (CMECs) under baseline and hypoxic conditions and to evaluate the expression, regulation and activation of eNOS, iNOS and PKB. The effect of PI3-K/PKB inhibition on NO production and eNOS expression/activation was also investigated. METHODS Adult rat cardiomyocytes and rat CMECs were made hypoxic by cell pelleting and low PO(2) incubation. Intracellular NO was measured by FACS analysis of DAF-2/DA fluorescence, and eNOS, iNOS and PKB were evaluated by Western blotting or flow cytometry. Upstream PKB inhibition was achieved with wortmannin. RESULTS (1) NO levels increased in both cell types after exposure to hypoxia. (2) In hypoxic CMECs, eNOS was upregulated and activated, no iNOS expression was observed and PKB was activated. (3) In myocytes, hypoxia did not affect eNOS expression, but increased its activation. Activated PKB also increased during hypoxia. FACS analysis showed increased iNOS in hypoxic myocytes. (4) Wortmannin resulted in decreased hypoxia-induced NO production and reduced activated eNOS levels. CONCLUSIONS Cardiomyocytes and CMECs show increased NO production during hypoxia. eNOS seems to be the main NOS isoform involved as source of the increased NO generation, although there may be a role for iNOS and other non-eNOS sources of NO in the hypoxic myocytes. Hypoxia-induced PKB and eNOS activation occurred simultaneously in both cell types, and the PI3-K/PKB pathway was associated with hypoxia-induced NO production via eNOS activation.
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Kravchenko NA, Yarmysh NV. Regulation of the expression of endothelial nitric oxide synthase and dysfunction of vascular endothelium in cardiovascular pathology. CYTOL GENET+ 2008. [DOI: 10.3103/s0095452708040117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ostergaard L, Stankevicius E, Andersen MR, Eskildsen-Helmond Y, Ledet T, Mulvany MJ, Simonsen U. Diminished NO release in chronic hypoxic human endothelial cells. Am J Physiol Heart Circ Physiol 2007; 293:H2894-903. [PMID: 17720765 DOI: 10.1152/ajpheart.01230.2006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The present study addressed whether chronic hypoxia is associated with reduced nitric oxide (NO) release due to decreased activation of endothelial NO synthase (eNOS). Primary cultures of endothelial cells from human umbilical veins (HUVECs) were used and exposed to different oxygen levels for 24 h, after which NO release, intracellular calcium, and eNOS activity and phosphorylation were measured after 24 h. Direct measurements using a NO microsensor showed that in contrast to 1-h exposure to 5% and 1% oxygen (acute hypoxia), histamine-evoked (10 μM) NO release from endothelial cells exposed to 5% and 1% oxygen for 24 h (chronic hypoxia) was reduced by, respectively, 58% and 40%. Furthermore, chronic hypoxia also lowered the amount and activity of eNOS enzyme. The decrease in activity could be accounted for by reduced intracellular calcium and altered eNOS phosphorylation. eNOS Ser1177 and eNOS Thr495 phosphorylations were reduced and increased, respectively, consistent with lowered enzyme activity. Akt kinase, which can phosphorylate eNOS Ser1177, was also decreased by hypoxia, regarding both total protein content and the phosphorylated (active) form. Moreover, the protein content of β- actin, which is known to influence the activity of eNOS, was almost halved by hypoxia, further supporting the fall in eNOS activity. In conclusion, chronic hypoxia in HUVECs reduces histamine-induced NO release as well as eNOS expression and activity. The decreased activity is most likely due to changed eNOS phosphorylation, which is supported by decreases in Akt expression and phosphorylation. By reducing NO, chronic hypoxia may accentuate endothelial dysfunction in cardiovascular disease.
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Control of Coronary Blood Flow During Hypoxemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 618:25-39. [DOI: 10.1007/978-0-387-75434-5_3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Natarajan R, Jones DG, Fisher BJ, Wallace TJ, Ghosh S, Fowler AA. Hypoxia inducible factor-1: regulation by nitric oxide in posthypoxic microvascular endothelium. Biochem Cell Biol 2006; 83:597-607. [PMID: 16234848 DOI: 10.1139/o05-047] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Microvascular endothelial cells provide a critical regulatory interface between blood constituents and tissue. Hypoxia inducible factor-1 (HIF-1) is a key transcription factor required for expression of hypoxia-dependent genes. We employed a model of hypoxia and reoxygenation (H/R) using the dermal microvascular endothelial cell line HMEC-1 to examine the effects of altered oxygen concentrations on microvascular HIF-1 expression and nitric oxide (NO) formation. Hypoxia increased inducible NO synthase (iNOS) mRNA in a time-dependent manner in HMEC-1. However, endothelial NO synthase mRNA progressively declined during hypoxia. H/R promoted significant increases in cellular nitrite levels that were significantly abrogated by the specific iNOS inhibitor N6-(1-iminoethyl)-L-lysine, di hy drochloride. Exogenous NO promoted stabilization of the alpha subunit of HIF-1 and produced functional DNA binding. Exposure of HMEC-1 to H/R resulted in previously unrecognized biphasic HIF-1alpha stabilization during reoxygenation. When the iNOS gene was silenced through the use of iNOS-specific small interfering RNA, HIF-1alpha stabilization and HIF-1 activation were dramatically diminished, suggesting that inducible NOS-derived NO is a key factor sustaining HIF-1 activation during both hypoxia and reoxygenation.
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Affiliation(s)
- Ramesh Natarajan
- Center for Vascular Inflammation Research, Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Box 980050, Virginia CommonwealthUniversity, Richmond, VA 23298, USA.
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Min J, Jin YM, Moon JS, Sung MS, Jo SA, Jo I. Hypoxia-induced endothelial NO synthase gene transcriptional activation is mediated through the tax-responsive element in endothelial cells. Hypertension 2006; 47:1189-96. [PMID: 16651461 DOI: 10.1161/01.hyp.0000222892.37375.4d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although hypoxia is known to induce upregulation of endothelial NO synthase (eNOS) gene expression, the underlying mechanism is largely unclear. In this study, we show that hypoxia increases eNOS gene expression through the binding of phosphorylated cAMP-responsive element binding (CREB) protein (pCREB) to the eNOS gene promoter. Hypoxia (1% O2) increased both eNOS expression and NO production, peaking at 24 hours, in bovine aortic endothelial cells, and these increases were accompanied by increases in pCREB. Treatment with the protein kinase A inhibitor H-89 or transfection with dominant-negative inhibitor of CREB reversed the hypoxia-induced increases in eNOS expression and NO production, with concomitant inhibition of the phosphorylation of CREB induced by hypoxia, suggesting an involvement of protein kinase A/pCREB-mediated pathway. To map the regulatory elements of the eNOS gene responsible for pCREB binding under hypoxia, we constructed an eNOS gene promoter (-1600 to +22 nucleotides) fused with a luciferase reporter gene [pGL2-eNOS(-1600)]. Hypoxia (for 24-hour incubation) increased the promoter activity by 2.36+/-0.18-fold in the bovine aortic endothelial cells transfected with pGL2-eNOS(-1600). However, progressive 5'-deletion from -1600 to -873 completely attenuated the hypoxia-induced increase in promoter activity. Electrophoretic mobility shift, anti-pCREB antibody supershift, and site-specific mutation analyses showed that pCREB is bound to the Tax-responsive element (TRE) site, a cAMP-responsive element-like site, located at -924 to -921 of the eNOS promoter. Our data demonstrate that the interaction between pCREB and the Tax-responsive element site within the eNOS promoter may represent a novel mechanism for the mediation of hypoxia-stimulated eNOS gene expression.
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Affiliation(s)
- Jiho Min
- Department of Biomedical Sciences, National Institute of Health, 194 Tongilo, Eunpyeong-gu, Seoul 122-701, Korea
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Strijdom H, Jacobs S, Hattingh S, Page C, Lochner A. Nitric oxide production is higher in rat cardiac microvessel endothelial cells than ventricular cardiomyocytes in baseline and hypoxic conditions: a comparative study. FASEB J 2005; 20:314-6. [PMID: 16354719 DOI: 10.1096/fj.05-4225fje] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
UNLABELLED The relative importance of endothelium- and cardiomyocyte-derived nitric oxide (NO) is unknown, with a lack of direct studies on cardiac microvessel endothelial cells (CMEC) and cardiomyocytes regarding relative cellular NO production. AIMS To assess and compare baseline and hypoxia-induced NO and ONOO- production in cardiomyocytes and CMEC. METHODS Rat cardiomyocytes were isolated, and cultured rat CMEC were purchased commercially. Hypoxia (+/- NOS inhibitors) was induced by mineral oil layering or hypoxic culture. NO and ONOO- were detected by FACS analysis of DAF-2/DA and DHR123, respectively. Total eNOS was determined by Western blot analysis. RESULTS 1) Baseline NO production in CMEC was sevenfold (cultured cells) and 26-fold (isolated cells) higher than in cardiomyocytes, 2) eNOS expression was 22-fold higher in CMEC, 3) hypoxia increased NO production in both cell types, albeit to a larger extent in CMEC, 4) in hypoxic cardiomyocytes, nonselective NOS and iNOS-specific inhibition attenuated NO production, whereas in CMEC, iNOS-specific inhibition was ineffective, and 5) baseline ONOO- production was 2.2 times greater in CMEC than in cardiomyocytes. CONCLUSION Using a novel approach, this study demonstrated that CMEC produce more baseline NO than cardiomyocytes, and that hypoxia activates NOS to increase NO production in both cell types. Baseline eNOS content was higher in CMEC than in cardiomyocytes, suggesting that differences in baseline NO production were eNOS-associated.
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Affiliation(s)
- Hans Strijdom
- Department of Medical Physiology and Biochemistry, Faculty of Health Sciences, Stellenbosch University, Tygerberg, Republic of South Africa.
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Ikeda Y, Biro S, Kamogawa Y, Yoshifuku S, Eto H, Orihara K, Yu B, Kihara T, Miyata M, Hamasaki S, Otsuji Y, Minagoe S, Tei C. Repeated Sauna Therapy Increases Arterial Endothelial Nitric Oxide Synthase Expression and Nitric Oxide Production in Cardiomyopathic Hamsters. Circ J 2005; 69:722-9. [PMID: 15914953 DOI: 10.1253/circj.69.722] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Vascular endothelial dysfunction is involved in the pathophysiology of chronic heart failure (CHF). It has been reported that sauna therapy, which allows thermal vasodilation, improves vascular endothelial dysfunction in patients with CHF. The present study investigates the mechanisms through which sauna therapy improves endothelial dysfunction induced by CHF. METHODS AND RESULTS Normal control and male TO-2 cardiomyopathic hamsters were used. Thirty-week-old TO-2 hamsters were treated daily with an experimental far infrared-ray dry sauna system for 15 min at 39 degrees C followed by 20 min at 30 degrees C. This procedure raised the rectal temperatures by about 1 degrees C. Arterial endothelial nitric oxide (NO) synthase (eNOS) mRNA and protein expressions were examined, and serum concentrations of nitrate were measured. The expression of eNOS mRNA in the aortas of normal controls did not change, whereas those of the TO-2 hamsters decreased with age. Four weeks of sauna therapy significantly increased eNOS mRNA expression in the aortas of TO-2 hamsters compared with those that did not undergo sauna therapy. Sauna therapy also upregulated aortic eNOS protein expression. Serum nitrate concentrations of the TO-2 hamsters were increased by 4 weeks of sauna therapy compared with those that did not undergo sauna. CONCLUSION Repeated sauna therapy increases eNOS expression and NO production in cardiomyopathic hamsters with heart failure.
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Affiliation(s)
- Yoshiyuki Ikeda
- Department of Cardiovascular, Respiratory and Metabolic Medicine, Graduate School of Medicine, Kagoshima University, Kogoshima, Japan
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Saed GM, Abu-Soud HM, Diamond MP. Role of nitric oxide in apoptosis of human peritoneal and adhesion fibroblasts after hypoxia. Fertil Steril 2004; 82 Suppl 3:1198-205. [PMID: 15474096 DOI: 10.1016/j.fertnstert.2004.04.034] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Revised: 04/22/2004] [Accepted: 04/22/2004] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To study the modulation of the inducible nitric oxide synthase/nitric oxide (iNOS/NO) expression system in fibroblasts isolated from human peritoneum and adhesion tissues by hypoxia. DESIGN Prospective experimental study. SETTING University medical center. PATIENT(S) Cultures of fibroblasts from both peritoneum and adhesion tissues of five patients. INTERVENTION(S) Hypoxia treatment of the primary cultured fibroblasts. MAIN OUTCOME MEASURE(S) We used Western and Northern blots to determine whether iNOS mRNA and its protein were present in peritoneal and adhesion fibroblasts and whether this expression is modulated by hypoxia. Multiplex reverse transcription polymerase chain reaction (RT-PCR) technique was used to quantify type I collagen mRNA in response to NG-nitro-L-arginine methyl ester (L-NAME). A terminal deoxynucleotidyl transferase mediated dUTP nick-end-labeling (TUNEL) assay was used to quantify apoptosis in response to NO donor S-nitro-N-acetyl-penicillamine (SNAP) treatment. A Griess assay was used to measure NO levels. RESULT(S) Peritoneal fibroblasts have significantly higher NO levels than adhesion fibroblasts. Hypoxia decreased NO in peritoneal fibroblasts to levels observed for adhesion fibroblasts. In addition, hypoxia increased both mRNA and protein levels of the iNOS gene in peritoneal and adhesion fibroblasts. Augmentation of NO by SNAP treatment increased apoptosis in adhesion fibroblasts. In contrast, SNAP had no effect on apoptosis of peritoneal fibroblasts. Inhibition of NO by L-NAME treatment increased type I collagen mRNA levels in peritoneal fibroblasts. CONCLUSION(S) Our findings confirm that adhesion fibroblasts produce less NO than normal peritoneal fibroblasts; NO may be the mechanism responsible for the creation and persistence of the adhesion phenotype.
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Affiliation(s)
- Ghassan M Saed
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Wayne State University School of Medicine, The C.S. Mott Center for Human Growth and Development, Detroit, Michigan 48201, USA.
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Abstract
Advances in our understanding of the molecular mechanisms involved in the constitutive and regulated expression of endothelial nitric oxide synthase (eNOS) mRNA expression present a new level of complexity to the study of endothelial gene regulation in health and disease. Recent studies highlight the contribution of both transcription and RNA stability to net steady-state mRNA levels of eNOS in vascular endothelium, introducing a new paradigm to gene regulation in the injured blood vessel. Constitutive eNOS expression is dependent on basal transcription machinery in the core promoter, involving positive and negative protein–protein and protein–DNA interactions. Chromatin-based mechanisms and epigenetic events also regulate expression of eNOS at the transcriptional level in a cell-restricted fashion. Although constitutively active, important physiological and pathophysiologic stimuli alter eNOS gene transcription rates. For instance, eNOS transcription rates increase in response to lysophosphatidylcholine, shear stress, and TGF-β, among others. Under basal conditions, eNOS mRNA is extremely stable. Surprisingly, posttranscriptional mechanisms have emerged as important regulatory pathways in the observed decreases in eNOS expression in some settings. In models of inflammation, proliferation/injury, oxidized low-density lipoprotein treatment, and hypoxia, eNOS mRNA destabilization plays a significant role in the rapid downregulation of eNOS mRNA levels.
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Affiliation(s)
- Sharon C Tai
- Renal Division and Department of Medicine, St. Michael's Hospital and University of Toronto, Ontario, Canada
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Chen JX, Meyrick B. Hypoxia increases Hsp90 binding to eNOS via PI3K-Akt in porcine coronary artery endothelium. J Transl Med 2004; 84:182-90. [PMID: 14661033 DOI: 10.1038/labinvest.3700027] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
This study examines the molecular mechanisms by which hypoxia regulates phosphorylated endothelial nitric oxide synthase (eNOS) activity and NO production in porcine coronary artery endothelial cells (PCAEC). Exposure to hypoxia (pO(2)=10 mmHg) for periods up to 3 h resulted in a time-dependent increase in eNOS protein expression and an early (15 min) and sustained increase in eNOS phosphorylation at Ser-1177. Exposure to hypoxia for 30 min led to a doubling in eNOS activity (control=6.2+/-4.4 vs hypoxia=14.1+/-5.0 fmol cGMP/microg protein, P<0.05) and NO release (control=5.9+/-0.8 vs hypoxia=11.8+/-1.2 nM/microg protein, P<0.05). Hypoxia also led to a significant increase in Akt phosphorylation and upregulation of Hsp90 binding to eNOS. Pretreatment of cells with either 1 microg/ml geldanamycin (a specific inhibitor of Hsp90) or 500 nM wortmannin (a specific PI3 kinase inhibitor) suppressed hypoxia-stimulated Akt and eNOS phosphorylation and significantly attenuated hypoxia-stimulated Hsp90 binding to eNOS. Both eNOS activity and NO production were inhibited by geldanamycin and wortmannin. Although hypoxia led to early activation of p42/44 mitogen-activated protein kinases (MAPK), inhibition of their pathway by PD98059 did not suppress hypoxia-stimulated eNOS phosphorylation and eNOS activity. These data demonstrate that hypoxia leads to increased eNOS phosphorylation via stimulated Hsp90 binding to eNOS and activation of the PI3-Akt pathway. We conclude that a coordinated interaction between Hsp90 and PI3-Akt may be an important mechanism by which eNOS activity and NO production is upregulated in hypoxic heart.
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Affiliation(s)
- Jian-xiong Chen
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Chen JX, Lawrence ML, Cunningham G, Christman BW, Meyrick B. HSP90 and Akt modulate Ang-1-induced angiogenesis via NO in coronary artery endothelium. J Appl Physiol (1985) 2003; 96:612-20. [PMID: 14555685 DOI: 10.1152/japplphysiol.00728.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study examines the notion that heat shock protein (HSP) 90 binding to nitric oxide (NO), endothelial NO synthase (eNOS), and PI3K-Akt regulate angiopoietin (Ang)-1-induced angiogenesis in porcine coronary artery endothelial cells (PCAEC). Exposure to Ang-1 (250 ng/ml) for periods up to 2 h resulted in a time-dependent increase in eNOS phosphorylation at Ser 1177 that occurred by 5 min and peaked at 60 min. This was accompanied by a gradual increase in NO release. Ang-1 also led to stimulation of HSP90 binding to eNOS and a significant increase in Akt phosphorylation. Thirty minutes of pretreatment of cells with either 1 microg/ml geldanamycin (a specific inhibitor of HSP90) or 500 nM wortmannin [a specific phosphatidylinositol 3 (PI3)-kinase (PI3K) inhibitor] significantly attenuated Ang-1-stimulated eNOS phosphorylation and NO production. Exposure to Ang-1 caused an increase in endothelial cell migration, tube formation, and sprouting from PCAEC spheroids, and pharmacological blockage of HSP90 function or inhibition of PI3K-Akt pathway completely abolished these effects. Inhibition of nitric oxide synthase by NG-nitro-l-arginine methyl ester (2.5 mM) also resulted in a significant decrease in Ang-1-induced angiogenesis. We conclude that stimulated HSP90 binding to eNOS and activation of the PI3-Akt pathway contribute to Ang-1-induced eNOS phosphorylation, NO production, and angiogenesis in PCAEC.
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Affiliation(s)
- Jian-xiong Chen
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2650, USA
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34
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Nase GP, Tuttle J, Bohlen HG. Reduced perivascular PO2 increases nitric oxide release from endothelial cells. Am J Physiol Heart Circ Physiol 2003; 285:H507-15. [PMID: 12860561 DOI: 10.1152/ajpheart.00759.2002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many studies have suggested that endothelial cells can act as "oxygen sensors" to large reductions in oxygen availability by increasing nitric oxide (NO) production. This study determined whether small reductions in oxygen availability enhanced NO production from in vivo intestinal arterioles, venules, and parenchymal cells. In vivo measurements of perivascular NO concentration ([NO]) were made with NO-sensitive microelectrodes during normoxic and reduced oxygen availability. During normoxia, intestinal first-order arteriolar [NO] was 397 +/- 26 nM (n = 5), paired venular [NO] was 298 +/- 34 nM (n = 5), and parenchymal cell [NO] was 138 +/- 36 nM (n = 3). During reduced oxygen availability, arteriolar and venular [NO] significantly increased to 695 +/- 79 nM (n = 5) and 534 +/- 66 nM (n = 5), respectively, whereas parenchymal [NO] remained unchanged at 144 +/- 34 nM (n = 4). During reduced oxygenation, arteriolar and venular diameters increased by 15 +/- 3% and 14 +/- 5%, respectively: NG-nitro-L-arginine methyl ester strongly suppressed the dilation to lower periarteriolar Po2. Micropipette injection of a CO2 embolus into arterioles significantly attenuated arteriolar dilation and suppressed NO release in response to reduced oxygen availability. These results indicated that in rat intestine, reduced oxygen availability increased both arteriolar and venular NO and that the main site of NO release under these conditions was from endothelial cells.
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Affiliation(s)
- G P Nase
- Dept. of Physiology and Biophysics, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
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35
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Harris MB, Blackstone MA, Ju H, Venema VJ, Venema RC. Heat-induced increases in endothelial NO synthase expression and activity and endothelial NO release. Am J Physiol Heart Circ Physiol 2003; 285:H333-40. [PMID: 12663266 DOI: 10.1152/ajpheart.00726.2002] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelial nitric oxide (NO) synthase (eNOS) is regulated by heat shock protein 90 (HSP90), a heat-inducible protein; however, the effect of heat shock on eNOS expression and eNO release is unknown. Bovine aortic endothelial cells were incubated for 1 h at 37 degrees C, 42 degrees C, or 45 degrees C and cell lysates were evaluated with the use of Western blotting. We observed a 2.1 +/- 0.1-fold increase in eNOS protein content, but no change in HSP90 content, HSP70 content, or HSP90/eNOS association, 24 h after heat shock at 42 degrees C. We also observed a 7.7 +/- 1.5-fold increase in HSP70 protein content, but did not observe a change in eNOS or HSP90 24 h after heat shock at 45 degrees C. eNOS activity and maximal bradykinin-stimulated NO release was significantly increased 24 h after heat shock at 42 degrees C. Heat shock in rats (core temperature: 42 degrees C, 15 min) resulted in a significant increase in aortic eNOS, HSP90, and HSP70 protein content. The aorta from heat-shocked rats exhibited a decreased maximal contractile response to phenylephrine, which was abolished by preincubation with NG-nitro-l-arginine. We conclude that prior heat shock is a physical stimulus of increased eNOS expression and is associated with an increase in eNOS activity, agonist-stimulated NO release, and a decreased vasoconstrictor response.
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Affiliation(s)
- M Brennan Harris
- Department of Pediatrics, Medical College of Georgia, Augusta, GA 30912-2500, USA.
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36
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Rattigan S, Barrett EJ, Clark MG. Insulin-mediated capillary recruitment in skeletal muscle: is this a mediator of insulin action on glucose metabolism? Curr Diab Rep 2003; 3:195-200. [PMID: 12762965 DOI: 10.1007/s11892-003-0063-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The possibility that insulin stimulates microvascular access for itself and glucose in muscle in vivo is discussed. The application of new techniques suggests that capillary recruitment is a normal part of insulin's action and that this process becomes impaired in insulin resistance. Exercise, which also leads to capillary recruitment, may involve a different mechanism than that used by insulin.
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Affiliation(s)
- Stephen Rattigan
- Biochemistry, Medical School, University of Tasmania, Private Bag 58, Hobart 7001, Australia.
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37
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Meini A, Benocci A, Frosini M, Sgaragli GP, Garcia JB, Pessina GP, Aldinucci C, Palmi M. Potentiation of intracellular Ca2+ mobilization by hypoxia-induced NO generation in rat brain striatal slices and human astrocytoma U-373 MG cells and its involvement in tissue damage. Eur J Neurosci 2003; 17:692-700. [PMID: 12603259 DOI: 10.1046/j.1460-9568.2003.02483.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The relationship between nitric oxide (NO) and intracellular Ca2+ in hypoxic-ischemic brain damage is not known in detail. Here we used rat striatal slices perfused under low-oxygen and Ca2+-free conditions and cultured human astrocytoma cells incubated under similar conditions as models to study the dynamics of intracellular NO and Ca2+ in hypoxia-induced tissue damage. Exposure of rat striatal slices for 70 min to low oxygen tension elicited a delayed and sustained increase in the release of 45Ca2+. This was potentiated by the NO donors sodium nitroprusside (SNP) and spermine-NO and inhibited by N-omega-nitro-L-arginine methyl ester (L-NAME) or by the NO scavenger 2-phenyl-4,4,5,5 tetramethylimidazoline-1-oxyl-3-oxide (PTIO). A membrane-permeant form of heparin in combination with either ruthenium red (RR) or ryanodine (RY) also inhibited 45Ca2+ release. In human astrocytoma U-373 MG cells, hypoxia increased intracellular Ca2+ concentration ([Ca2+]i) by 67.2 +/- 13.1% compared to normoxic controls and this effect was inhibited by L-NAME, PTIO or heparin plus RR. In striatal tissue, hypoxia increased NO production and LDH release and both effects were antagonized by L-NAME. Although heparin plus RR or RY antagonized hypoxia-induced increase in LDH release they failed to counteract increased NO production. These data therefore indicate that NO contributes to hypoxic damage through increased intracellular Ca2+ mobilization from endoplasmic reticulum and suggest that the NO-Ca2+ signalling might be a potential therapeutic target in hypoxia-induced neuronal degeneration.
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Affiliation(s)
- Antonella Meini
- Istituto di Scienze Farmacologiche, Università di Siena, via A Moro 2, 53100 Siena, Italy
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38
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Cai WJ, Koltai S, Kocsis E, Scholz D, Kostin S, Luo X, Schaper W, Schaper J. Remodeling of the adventitia during coronary arteriogenesis. Am J Physiol Heart Circ Physiol 2003; 284:H31-40. [PMID: 12388238 DOI: 10.1152/ajpheart.00478.2002] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We studied the role of the adventitia in adaptive arteriogenesis during the phase of active growth of coronary collateral vessels (CV) induced by chronic occlusion of the left circumflex coronary artery in canine hearts. We used electron microscopy and immunoconfocal (IF) labeling for bFGF, matrix metalloproteinase (MMP)-2, MMP-9, tissue-type plasminogen activator (tPA), its inhibitor (PAI-1), fibronectin (FN), and Ki-67. Proliferation of smooth muscle cells and adventitial fibroblasts was evident. Quantitative IF showed that adventitial MMP-2, MMP-9, and FN were 9.2-, 7.5-, and 8.6-fold, bFGF was 5.1-fold, and PAI-1 was 3.4-fold higher in CV than in normal vessels (NV). The number of fibroblasts was 5-fold elevated in CV, but the elastic fiber content was 25-fold greater in NV than in CV. Perivascular myocyte damage and induction of endothelial nitric oxide synthase in peri-CV capillaries indicate expansion of CV. It was concluded that adventitial activation is associated with the development of CV through cell proliferation, production of growth factors, and induction of extracellular proteolysis thereby contributing to remodeling during adaptive arteriogenesis.
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Affiliation(s)
- Wei-Jun Cai
- Max Planck Institute, Department of Experimental Cardiology, D-61231 Bad Nauheim, Germany
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Li H, Wallerath T, Münzel T, Förstermann U. Regulation of endothelial-type NO synthase expression in pathophysiology and in response to drugs. Nitric Oxide 2002; 7:149-64. [PMID: 12381413 DOI: 10.1016/s1089-8603(02)00111-8] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In many types of cardiovascular pathophysiology such as hypercholesterolemia and atherosclerosis, diabetes, cigarette smoking, or hypertension (with its sequelae stroke and heart failure) the expression of endothelial NO synthase (eNOS) is altered. Both up- and downregulation of eNOS have been observed, depending on the underlying disease. When eNOS is upregulated, the upregulation is often futile and goes along with a reduction in bioactive NO. This is due to an increased production of superoxide generated by NAD(P)H oxidase and by an uncoupled eNOS. A number of drugs with favorable effects on cardiovascular disease upregulate eNOS expression. The resulting increase in vascular NO production may contribute to their beneficial effects. These compounds include statins, angiotensin-converting enzyme inhibitors, AT1 receptor antagonists, calcium channel blockers, and some antioxidants. Other drugs such as glucocorticoids, whose administration is associated with cardiovascular side effects, downregulate eNOS expression. Stills others such as the immunosuppressants cyclosporine A and FK506/tacrolimus or erythropoietin have inconsistent effects on eNOS. Thus regulation of eNOS expression and activity contributes to the overall action of several classes of drugs, and the development of compounds that specifically upregulate this protective enzyme appears as a desirable target for drug development.
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Affiliation(s)
- Huige Li
- Department of Pharmacology, Johannes Gutenberg University, Obere Zahlbacher Strasse 67, D-55101, Mainz, Germany
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Danton GH, Prado R, Truettner J, Watson BD, Dietrich WD. Endothelial nitric oxide synthase pathophysiology after nonocclusive common carotid artery thrombosis in rats. J Cereb Blood Flow Metab 2002; 22:612-9. [PMID: 11973434 DOI: 10.1097/00004647-200205000-00013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although vascular dysregulation has been documented in patients with extracranial vascular disease, transient ischemic attacks, and stroke, the pathomechanisms are poorly understood. To model thromboembolic stroke in rats, photochemically induced nonocclusive common carotid artery thrombosis (CCAT) was used to generate a platelet thrombus in the carotid artery of anesthetized rats. After CCAT, platelet aggregates break off the thrombus, travel to the distal cerebral vasculature, damage blood vessels, and cause small infarctions. The authors hypothesized that deficits in the endothelial nitric oxide synthase (eNOS) pathway may be responsible for vascular dysfunction after embolic stroke. To examine the functional status of the eNOS system, they measured eNOS-dependent dilation after CCAT by applying acetylcholine through a cranial window over the middle cerebral artery. The authors also measured eNOS mRNA and protein in the middle cerebral artery to determine whether functional changes were caused by alterations in expression. eNOS-dependent dilation was reduced at 6 hours, elevated at 24 hours, and returned to baseline 72 hours after CCAT. Endothelial nitric oxide synthase mRNA increased at 2 hours and was followed by a rise in protein 24 hours after CCAT. Changes in the eNOS system may account for some of the observed vascular deficits in patients with cerebrovascular disease.
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Affiliation(s)
- Gary H Danton
- Department of Neurological Surgery, University of Miami School of Medicine, Miami, FL 33101, U.S.A
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41
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Kerkhof CJM, Van Der Linden PJW, Sipkema P. Role of myocardium and endothelium in coronary vascular smooth muscle responses to hypoxia. Am J Physiol Heart Circ Physiol 2002; 282:H1296-303. [PMID: 11893564 DOI: 10.1152/ajpheart.00179.2001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypoxia triggers a mechanism that induces vasodilation in the whole heart but not necessarily in isolated coronary arteries. We therefore studied the role of cardiomyocytes (CM), smooth muscle cells (SMC), and endothelial cells (EC) in coronary responses to hypoxia (PO(2) of 5-10 mmHg). In an attempt to determine the factor(s) released in response to hypoxia, we inhibited the contribution of adenosine, ATP-sensitive K(+) channels, prostaglandins, and nitric oxide. Isolated rat septal artery segments without (-T) and with a layer of cardiac tissue (+T) were mounted in a double wire myograph, and constriction was induced. Hypoxia induced a decrease in isometric force of 21% and 61% in -T and +T segments, respectively (P < 0.05). EC removal increased the relaxation to hypoxia in -T segments to 33% but had the same effect in +T segments (61%). Only one of the inhibitors, the adenosine antagonist in +T segments, partially affected the relaxation due to hypoxia. The role of adenosine is thus limited and other mechanisms have to contribute. We conclude that hypoxia induces a relaxation of SMC that is augmented by the presence of CM and blunted by the endothelium. A single mediator does not induce those effects.
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Affiliation(s)
- Cornel J M Kerkhof
- Laboratory for Physiology, Institute for Cardiovascular Research, Vrije Universiteit, Amsterdam 1081 BT, The Netherlands
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42
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Wierema TKA, Houben AJHM, Kroon AA, Koster D, Zander KVANDER, Engelshoven JMAVAN, Leeuw PWDE. Nitric oxide dependence of renal blood flow in patients with renal artery stenosis. J Am Soc Nephrol 2001; 12:1836-1843. [PMID: 11518776 DOI: 10.1681/asn.v1291836] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In ischemia, nitric oxide (NO) production is increased, possibly to preserve flow. The role of NO was investigated in hypertensive patients with or without renal artery stenosis (RAS). Fifty-five hypertensive patients scheduled to undergo diagnostic renal angiography underwent mean renal blood flow (MRBF) measurements before and after an intrarenal injection of the NO synthase blocker N(g)-monomethyl-L-arginine (L-NMMA) at 0.03 microg/kg, before angiography. A dose-response study indicated that this dose of L-NMMA significantly blocked NO synthesis. MRBF was measured at baseline and 1, 5, 10, and 20 min after L-NMMA treatment. On the basis of the angiographic results, patients were divided into three diagnostic categories, i.e., essential hypertension (n = 26), unilateral RAS (n = 16), or bilateral RAS (n = 8). In essential hypertension, MRBF was decreased by 18 +/- 4% at 20 min. In unilateral RAS, L-NMMA did not affect MRBF in the stenotic kidney but reduced MRBF in the nonstenotic kidney by 40 +/- 9% at 20 min. In bilateral RAS, L-NMMA reduced flow by 32 +/- 14% at 20 min. In the nonstenotic kidney in unilateral RAS, a positive correlation was observed between the effect of NO blockade on MRBF and arterial renin levels (P = 0.009). In the stenotic kidney, in contrast, this correlation was inverse (P = 0.007). In conclusion, MRBF depends on NO in hypertensive patients, except in the stenotic kidney in unilateral RAS. In the nonstenotic kidney in unilateral RAS, NO bioavailability is increased. It is suggested that a compensatory mechanism, regulated by NO and possibly angiotensin II, may preserve renal function.
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Affiliation(s)
- Thomas K A Wierema
- Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Alphons J H M Houben
- Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Abraham A Kroon
- Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Derk Koster
- Department of Radiology, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Kim VAN DER Zander
- Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Jos M A VAN Engelshoven
- Department of Radiology, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Peter W DE Leeuw
- Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
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Rydén M, Elizalde M, van Harmelen V, Ohlund A, Hoffstedt J, Bringman S, Andersson K. Increased expression of eNOS protein in omental versus subcutaneous adipose tissue in obese human subjects. Int J Obes (Lond) 2001; 25:811-5. [PMID: 11439294 DOI: 10.1038/sj.ijo.0801625] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2000] [Revised: 01/04/2001] [Accepted: 01/18/2001] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To investigate the expression of eNOS and iNOS mRNA and protein in adipose tissue from subcutaneous (s.c.) and omental adipose tissue of obese subjects. DESIGN Subcutaneous and omental adipose tissue was obtained from subjects undergoing weight reduction surgery. Messenger RNA and protein levels were measured in tissue extracts and related to basal lipolysis, which was measured in isolated adipocytes from the same subjects. SUBJECTS Eight overweight but otherwise healthy male subjects (age 43.4+/-10.3 y, BMI 39+/-3.5 kg/m(2), mean+/-s.e.m.). MEASUREMENTS For mRNA detection a competitive reverse transcription polymerase chain reaction method was used while protein was detected by Western blot. Glycerol release was determined in isolated adipocytes using a standard luminometric assay. RESULTS Tissue mRNA levels for eNOS in s.c. tissue were 6098+/-1969 amol/mg RNA and in omental tissue 6987+/-2914 amol/mg RNA (mean+/-s.e.m., P=0.75). iNOS mRNA levels were substantially lower; in s.c. tissue 227+/-127 amol/mg RNA and in omental tissue 245+/-162 amol/mg RNA (P=0.8). In Western blot, eNOS protein levels in s.c. and omental tissue were 1.88+/-2.0 and 7.47+/-4.11 (OD/mm(2) 100 microg total protein, P=0.0063), respectively. iNOS protein was expressed at significantly lower levels and barely detectable in both s.c. and omental tissue. Basal rate of lipolysis was two times higher in s.c. compared to omental fat cells (P=0.028). CONCLUSIONS eNOS protein is markedly increased in omental compared to s.c. adipose tissue in human obese subjects, probably due to post-transcriptional mechanisms. Since basal lipolysis is much lower in omental vs s.c. adipose tissue it is possible that regionally increased NO production, primarily by eNOS, may be involved in the site difference of basal lipolysis in obese subjects.
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Affiliation(s)
- M Rydén
- Centre for Metabolism and Endocrinology, Department of Medicine, Karolinska Institutet, Huddinge University Hospital, 141 86 Huddinge, Sweden.
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Abstract
Nitric oxide (NO) is a potent vasodilator and inhibitor of vascular remodeling. Reduced NO production has been implicated in the pathophysiology of pulmonary hypertension, with endothelial NO synthase (NOS) knockout mice showing an increased risk for pulmonary hypertension. Because molecular oxygen (O2) is an essential substrate for NO synthesis by the NOSs and biochemical studies using purified NOS isoforms have estimated the Michaelis-Menten constant values for O2 to be in the physiological range, it has been suggested that O2 substrate limitation may limit NO production in various pathophysiological conditions including hypoxia. This review summarizes numerous studies of the effects of acute and chronic hypoxia on NO production in the lungs of humans and animals as well as in cultured vascular cells. In addition, the effects of hypoxia on NOS expression and posttranslational regulation of NOS activity by other proteins are also discussed. Most studies found that hypoxia limits NO synthesis even when NOS expression is increased.
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Affiliation(s)
- T D Le Cras
- Pediatric Heart Lung Center, Department of Pediatrics, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
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45
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Dachs GU, Tozer GM. Hypoxia modulated gene expression: angiogenesis, metastasis and therapeutic exploitation. Eur J Cancer 2000; 36:1649-60. [PMID: 10959051 DOI: 10.1016/s0959-8049(00)00159-3] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tumour hypoxia is the result of an imbalance in oxygen supply and demand. It is an adverse prognostic indicator in cancer as it modulates tumour progression and treatment. Many genes controlling tumour biology are oxygen regulated, and new ones are constantly added to the growing list of hypoxia-induced genes. Of specific importance are hypoxia-responsive transcription factors, as they can modulate the expression of numerous different genes. Similarly, growth factors which govern the formation of new blood vessels or which control blood flow are vitally important for both the maintenance of the primary tumour and metastases at distant sites. The purpose of this review is to present an update of selected issues regarding hypoxia-inducible gene expression and how this affects prognosis, angiogenesis and metastasis. It will conclude by discussing gene therapy as one possible means of exploiting tumour hypoxia for the treatment of cancer.
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Affiliation(s)
- G U Dachs
- Tumour Microcirculation Group, Gray Laboratory Cancer Research Trust, PO Box 100, Mount Vernon Hospital, HA6 2JR, Northwood, UK
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