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Edgar KS, Cunning C, Gardiner TA, McDonald DM. BH4 supplementation reduces retinal cell death in ischaemic retinopathy. Sci Rep 2023; 13:21292. [PMID: 38042898 PMCID: PMC10693630 DOI: 10.1038/s41598-023-48167-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
Dysregulation of nitric oxide (NO) production can cause ischaemic retinal injury and result in blindness. How this dysregulation occurs is poorly understood but thought to be due to an impairment in NO synthase function (NOS) and nitro-oxidative stress. Here we investigated the possibility of correcting this defective NOS activity by supplementation with the cofactor tetrahydrobiopterin, BH4. Retinal ischaemia was examined using the oxygen-induced retinopathy model and BH4 deficient Hph-1 mice used to establish the relationship between NOS activity and BH4. Mice were treated with the stable BH4 precursor sepiapterin at the onset of hypoxia and their retinas assessed 48 h later. HPLC analysis confirmed elevated BH4 levels in all sepiapterin supplemented groups and increased NOS activity. Sepiapterin treatment caused a significant decrease in neuronal cell death in the inner nuclear layer that was most notable in WT animals and was associated with significantly diminished superoxide and local peroxynitrite formation. Interestingly, sepiapterin also increased inflammatory cytokine levels but not microglia cell number. BH4 supplementation by sepiapterin improved both redox state and neuronal survival during retinal ischaemia, in spite of a paradoxical increase in inflammatory cytokines. This implicates nitro-oxidative stress in retinal neurones as the cytotoxic element in ischaemia, rather than enhanced pro-inflammatory signalling.
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Affiliation(s)
- Kevin S Edgar
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, 97 Lisburn Road, BT9 7BL, UK
| | - Ciara Cunning
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, 97 Lisburn Road, BT9 7BL, UK
| | - Tom A Gardiner
- School of Medicine, Dentistry and Biomedical Sciences, Centre for Biomedical Sciences Education, Queen's University Belfast, Belfast, UK
| | - Denise M McDonald
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, 97 Lisburn Road, BT9 7BL, UK.
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2
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Nitric Oxide Signaling for Actinorhodin Production in Streptomyces coelicolor A3(2) via the DevS/R Two-Component System. Appl Environ Microbiol 2021; 87:e0048021. [PMID: 33990302 DOI: 10.1128/aem.00480-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nitric oxide (NO) is an important signaling molecule in eukaryotic and prokaryotic cells. A previous study revealed an NO synthase-independent NO production metabolic cycle in which the three nitrogen oxides, nitrate (NO3-), nitrite (NO2-), and NO, were generated in the actinobacterium Streptomyces coelicolor A3(2). NO was suggested to act as a signaling molecule, functioning as a hormone that regulates secondary metabolism. Here, we demonstrate the NO-mediated regulation of the production of the blue-pigmented antibiotic actinorhodin (ACT), via the heme-based DevS/R two-component system (TCS). Intracellular NO controls the stabilization or inactivation of DevS, depending on the NO concentration. An electrophoretic mobility shift assay and chromatin immunoprecipitation-quantitative PCR analysis revealed the direct binding between DevR and the promoter region of actII-ORF4, resulting in gene expression. Our results indicate that NO regulates the DevS/R TCS, thereby strictly controlling the secondary metabolism of S. coelicolor A3(2). IMPORTANCE Diverse organisms, such as mammals, plants, and bacteria, utilize NO via well-known signal transduction mechanisms. Many useful secondary metabolite-producing bacteria of the Streptomyces genus had been also suggested for the metabolism regulated by endogenously produced NO; however, the regulatory mechanisms remain to be elucidated. In this study, we demonstrated the molecular mechanism by which endogenously produced NO regulates antibiotic production via the DevS/R TCS in S. coelicolor A3(2). NO serves as both a stabilizer and a repressor in the regulation of antibiotic production. This report shows the mechanism by which Streptomyces utilizes endogenously produced NO to modulate its normal life cycle. Moreover, this study implies that studying NO signaling in actinobacteria can help in the development of both clinical strategies against pathogenic actinomycetes and the actinobacterial industries.
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3
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Huang M, Li J. Physiological regulation of reactive oxygen species in organisms based on their physicochemical properties. Acta Physiol (Oxf) 2020; 228:e13351. [PMID: 31344326 DOI: 10.1111/apha.13351] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 07/21/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022]
Abstract
Oxidative stress is recognized as free radical dyshomeostasis, which has damaging effects on proteins, lipids and DNA. However, during cell differentiation and proliferation and other normal physiological processes, free radicals play a pivotal role in message transmission and are considered important messengers. Organisms maintain free radical homeostasis through a sophisticated regulatory system in which these "2-faced" molecules play appropriate roles under physiological and pathological conditions. Reactive oxygen species (ROS), including a large number of free radicals, act as redox signalling molecules in essential cellular signalling pathways, including cell differentiation and proliferation. However, excessive ROS levels can induce oxidative stress, which is an important risk factor for diabetes, cancer and cardiovascular disease. An overall comprehensive understanding of ROS is beneficial for understanding the pathogenesis of certain diseases and finding new therapeutic treatments. This review primarily focuses on ROS cellular localization, sources, chemistry and molecular targets to determine how to distinguish between the roles of ROS as messengers and in oxidative stress.
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Affiliation(s)
- Mei‐Zhou Huang
- Key Lab of New Animal Drug Project of Gansu Province, Key Lab of Veterinary Pharmaceutical Development of Ministry of Agriculture Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS Lanzhou China
| | - Jian‐Yong Li
- Key Lab of New Animal Drug Project of Gansu Province, Key Lab of Veterinary Pharmaceutical Development of Ministry of Agriculture Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS Lanzhou China
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Lourenço CF, Ledo A, Caetano M, Barbosa RM, Laranjinha J. Age-Dependent Impairment of Neurovascular and Neurometabolic Coupling in the Hippocampus. Front Physiol 2018; 9:913. [PMID: 30065657 PMCID: PMC6056650 DOI: 10.3389/fphys.2018.00913] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/21/2018] [Indexed: 11/24/2022] Open
Abstract
Neurovascular and neurometabolic coupling are critical and complex processes underlying brain function. Perturbations in the regulation of these processes are, likely, early dysfunctional alterations in pathological brain aging and age-related neurodegeneration. Evidences support the role of nitric oxide (•NO) as a key messenger both in neurovascular coupling, by signaling from neurons to blood vessels, and in neurometabolic coupling, by modulating O2 utilization by mitochondria. In the present study, we investigated the functionality of neurovascular and neurometabolic coupling in connection to •NO signaling and in association to cognitive performance during aging. For this, we performed in vivo simultaneous measurements of •NO, O2 and cerebral blood flow (CBF) in the hippocampus of F344 rats along chronological age in response to glutamatergic activation and in correlation with cognitive performance. Firstly, it is evidenced the temporal sequence of events upon glutamate stimulation of hippocampal dentate gyrus, encompassing the local and transitory increase of •NO followed by transitory local changes of CBF and pO2. Specifically, the transient increase of •NO is followed by an increase of CBF and biphasic changes of the local pO2. We observed that, although the glutamate-induced •NO dynamics were not significantly affected by aging, the correspondent hemodynamic was progressively diminished accompanying a decline in learning and memory. Noteworthy, in spite of a compromised blood supply, in aged rats we observed an increased ΔpO2 associated to the hemodynamic response, suggestive of a decrease in the global metabolic rate of O2. Furthermore, the impairment in the neurovascular coupling observed along aging in F344 rats was mimicked in young rats by promoting an unbalance in redox status toward oxidation via intracellular generation of superoxide radical. This observation strengthens the idea that oxidative stress may have a critical role in the neurovascular uncoupling underlying brain aging and dysfunction. Overall, data supports an impairment of neurovascular response in connection with cognition decline due to oxidative environment-dependent compromised •NO signaling from neurons to vessels during aging.
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Affiliation(s)
- Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana Ledo
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Miguel Caetano
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Rui M Barbosa
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
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Neuronal nitric oxide synthase regulation of skeletal muscle functional hyperemia: exercise training and moderate compensated heart failure. Nitric Oxide 2017; 74:1-9. [PMID: 29288804 DOI: 10.1016/j.niox.2017.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/15/2017] [Accepted: 12/24/2017] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO) modulates oxygen delivery-utilization matching in resting and contracting skeletal muscle. Recent reports indicate that neuronal NO synthase (nNOS)-mediated vasoregulation during contractions is enhanced with exercise training and impaired with chronic heart failure (HF). Consequently, we tested the hypothesis that selective nNOS inhibition (S-methyl-l-thiocitrulline; SMTC, 2.1 μmol/kg) would produce attenuated reductions in muscle blood flow during moderate/heavy submaximal exercise in sedentary HF rats compared to their healthy counterparts. In addition, SMTC was expected to evoke greater reductions in exercising muscle blood flow in trained compared to sedentary healthy and HF rats. Blood flow during submaximal treadmill running (20 min/m, 5% grade) was determined via radiolabeled microspheres pre- and post-SMTC administration in healthy sedentary (Healthy + Sed, n = 8), healthy exercise trained (Healthy + ExT, n = 8), HF sedentary (HF + Sed, left ventricular end-diastolic pressure (LVEDP) = 12 ± 1 mmHg, n = 8), and HF exercise trained (HF + ExT, LVEDP = 16 ± 2 mmHg, n = 7) rats. nNOS contribution to exercising total hindlimb blood flow (ml/min/100 g) was not increased by training in either healthy or HF groups (Healthy + Sed: 105 ± 11 vs. 108 ± 16; Healthy + ExT: 96 ± 9 vs. 91 ± 7; HF + Sed: 124 ± 6 vs. 110 ± 12; HF + ExT: 107 ± 13 vs. 101 ± 8; control vs. SMTC, respectively; p > .05 for all). Similarly, SMTC did not reduce exercising blood flow in the majority of individual hindlimb muscles in any group (p > .05 for all, except for the semitendinosus and adductor longus in HF + Sed and the adductor longus in HF + ExT; p < .05). Contrary to our hypothesis, we find no support for either upregulation of nNOS function contributing to exercise hyperemia after training or its dysregulation with chronic HF.
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Ghimire K, Altmann HM, Straub AC, Isenberg JS. Nitric oxide: what's new to NO? Am J Physiol Cell Physiol 2016; 312:C254-C262. [PMID: 27974299 PMCID: PMC5401944 DOI: 10.1152/ajpcell.00315.2016] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/12/2016] [Accepted: 12/12/2016] [Indexed: 01/22/2023]
Abstract
Nitric oxide (NO) is one of the critical components of the vasculature, regulating key signaling pathways in health. In macrovessels, NO functions to suppress cell inflammation as well as adhesion. In this way, it inhibits thrombosis and promotes blood flow. It also functions to limit vessel constriction and vessel wall remodeling. In microvessels and particularly capillaries, NO, along with growth factors, is important in promoting new vessel formation, a process termed angiogenesis. With age and cardiovascular disease, animal and human studies confirm that NO is dysregulated at multiple levels including decreased production, decreased tissue half-life, and decreased potency. NO has also been implicated in diseases that are related to neurotransmission and cancer although it is likely that these processes involve NO at higher concentrations and from nonvascular cell sources. Conversely, NO and drugs that directly or indirectly increase NO signaling have found clinical applications in both age-related diseases and in younger individuals. This focused review considers recently reported advances being made in the field of NO signaling regulation at several levels including enzymatic production, receptor function, interacting partners, localization of signaling, matrix-cellular and cell-to-cell cross talk, as well as the possible impact these newly described mechanisms have on health and disease.
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Affiliation(s)
- Kedar Ghimire
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Helene M Altmann
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Adam C Straub
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Jeffrey S Isenberg
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania; .,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; and.,Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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7
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Slyvka Y, Malgor R, Inman SR, Ding J, Heh V, Nowak FV. Antioxidant diet and sex interact to regulate NOS isoform expression and glomerular mesangium proliferation in Zucker diabetic rat kidney. Acta Histochem 2016; 118:183-93. [PMID: 26797190 DOI: 10.1016/j.acthis.2015.12.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/30/2015] [Accepted: 12/31/2015] [Indexed: 12/21/2022]
Abstract
Oxidative stress contributes substantially to the pathophysiology of diabetic nephropathy (DN). Consumption of an antioxidant-fortified (AO) diet from an early age prevents or delays later development of DN in the Zucker rat female with type 2 diabetes. We hypothesize this is due to effects on mesangial matrix and renal nitric oxide synthase (NOS) distribution and to sex-specific differences in NOS responses in the diabetic kidney. Total glomerular tuft area (GTA) and PAS-positive tuft area (PTA), endothelial (e), neuronal (n) and inducible (i) NOS were quantified in males and females on AO or regular (REG) diet at 6 and 20 weeks of age. eNOS was observed in glomeruli and tubules. nNOS predominantly localized to tubular epithelium in both cortex and medulla. iNOS was expressed in proximal and distal tubules and collecting ducts. Sex, diabetes duration and AO diet affected the distribution of the three isoforms. GTA and PTA increased with duration of hyperglycemia and showed a negative correlation with renal levels of all NOS isoforms. AO diet in both genders was associated with less PAS-positive staining and less mesangial expansion than the REG diet, an early increase in cortical iNOS in males, and sex-specific changes in cortical eNOS at 20 weeks. These effects of AO diet may contribute to sex-specific preservation of renal function in females.
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Affiliation(s)
- Yuriy Slyvka
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA; The Diabetes Institute at Ohio University, Ohio University, Athens, OH 45701, USA
| | - Ramiro Malgor
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA; Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA; The Diabetes Institute at Ohio University, Ohio University, Athens, OH 45701, USA
| | - Sharon R Inman
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA; Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA; The Diabetes Institute at Ohio University, Ohio University, Athens, OH 45701, USA
| | - Julia Ding
- College of Natural Sciences, School of Biological Sciences, University of Texas at Austin, TX 78713, USA
| | - Victor Heh
- OUHCOM Office of Research & Grants, Ohio University, Athens, OH 45701, USA
| | - Felicia V Nowak
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA; Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA; The Diabetes Institute at Ohio University, Ohio University, Athens, OH 45701, USA.
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8
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Lamrani M, Sassi N, Paul C, Yousfi N, Boucher JL, Gauthier N, Labbé J, Seignez C, Racoeur C, Athias A, Guerreiro R, Vergely C, Rochette L, Bettaieb A, Jeannin JF. TLR4/IFNγ pathways induce tumor regression via NOS II-dependent NO and ROS production in murine breast cancer models. Oncoimmunology 2015; 5:e1123369. [PMID: 27467924 DOI: 10.1080/2162402x.2015.1123369] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/17/2015] [Accepted: 11/17/2015] [Indexed: 02/07/2023] Open
Abstract
Toll-like receptor (TLR) 4 agonists have emerged as a new group of molecules used for cancer therapy. They have been exploited to enhance the immunogenicity of current chemotherapeutic regimens. However, their effects on cancer cells remain elusive. Here, we showed that a TLR4 agonist, namely a synthetic lipid A analog (ALA), OM-174, exhibits antitumor effects in several mammary tumor mouse models. We also showed that immune components are involved in such effects, as attested to by the failure of ALA to induce tumor regression or an increase of animal survival in mice knocked-out for interferon γ (IFNγ) or TLR4. TLR4 and IFNγ receptor (INFR2) expressed by cancer cells are involved in the antitumor efficacy of ALA since this last did not inhibit tumor growth in mice bearing a tumor but lacking TLR4 or IFNγ receptor 2 (IFNR2). Mechanistic investigations revealed that nitric oxide (NO), superoxide and peroxynitrite produced by uncoupling of inducible NO synthase (NOS II) in cancer cells are key mediators of ALA and IFNγ-mediated tumor growth inhibition. We present here a comprehensive picture of tumor cell death induction, in vivo and in vitro, by immunotherapy and for the first time the involvement of the TLR4/IFNγ/NOS II pathway in immunotherapy was investigated.
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Affiliation(s)
- Myriam Lamrani
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France; INSERM U 866, Burgundy University, Dijon, France
| | - Nejia Sassi
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France; INSERM U 866, Burgundy University, Dijon, France
| | - Catherine Paul
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France; INSERM U 866, Burgundy University, Dijon, France
| | - Nadhir Yousfi
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France
| | | | - Nolwenn Gauthier
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; INSERM U 866, Burgundy University, Dijon, France
| | - Jérôme Labbé
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; INSERM U 866, Burgundy University, Dijon, France
| | - Cédric Seignez
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France; INSERM U 866, Burgundy University, Dijon, France
| | - Cindy Racoeur
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France; INSERM U 866, Burgundy University, Dijon, France
| | - Anne Athias
- INSERM U 866, Burgundy University , Dijon, France
| | | | | | - Luc Rochette
- INSERM U 866, Burgundy University , Dijon, France
| | - Ali Bettaieb
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France; INSERM U 866, Burgundy University, Dijon, France
| | - Jean-François Jeannin
- EPHE, PSL Research University, Laboratoire d'Immunologie et Immunothérapie des Cancers, F-75014, Paris, France; Univ. Bourgogne Franche-Comté, LIIC EA7269, Dijon, France; INSERM U 866, Burgundy University, Dijon, France
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Xie L, Talukder MAH, Sun J, Varadharaj S, Zweier JL. Liposomal tetrahydrobiopterin preserves eNOS coupling in the post-ischemic heart conferring in vivo cardioprotection. J Mol Cell Cardiol 2015; 86:14-22. [PMID: 26116866 PMCID: PMC4558339 DOI: 10.1016/j.yjmcc.2015.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/17/2015] [Accepted: 06/19/2015] [Indexed: 02/07/2023]
Abstract
Tetrahydrobiopterin (BH4) is an essential cofactor of nitric oxide synthase (NOS), and reduced BH4 availability leads to endothelial NOS (eNOS) uncoupling and increased reactive oxygen species (ROS) generation. Questions remain regarding the functional state of eNOS and role of BH4 availability in the process of in vivo myocardial ischemia-reperfusion (I/R) injury. Rats were subjected to 60min of in vivo left coronary artery occlusion and varying periods of reperfusion with or without pre-ischemic liposomal BH4 supplementation (1mg/kg, iv). Myocardial infarction was correlated with cardiac BH4 content, eNOS protein level, NOS enzyme activity, and ROS generation. In the vehicle group, 60-min ischemia drastically reduced myocardial BH4 content in the area at risk (AAR) compared to non-ischemic (NI) area and the level remained lower during early reperfusion followed by recovery after 24-h reperfusion. Total eNOS, activated eNOS protein level (eNOS Ser1177 phosphorylation) and NOS activity were also significantly reduced during ischemia and/or early reperfusion, but recovered after 24-h reperfusion. With liposomal BH4 treatment, BH4 levels were identical in the AAR and NI area during ischemia and/or early reperfusion, and were significantly higher than with vehicle. BH4 pre-treatment preserved eNOS Ser1177 phosphorylation and NOS activity in the AAR, and significantly reduced myocardial ROS generation and infarction compared to vehicle. These findings provide direct evidence that in vivo I/R induces eNOS dysfunction secondary to BH4 depletion, and that pre-ischemic liposomal BH4 administration preserves eNOS function conferring cardioprotection with reduced oxidative stress.
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Affiliation(s)
- Lin Xie
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA; The Institute of Organ Transplantation, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - M A Hassan Talukder
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jian Sun
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Saradhadevi Varadharaj
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jay L Zweier
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA.
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10
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Khan M, Dhammu TS, Matsuda F, Singh AK, Singh I. Blocking a vicious cycle nNOS/peroxynitrite/AMPK by S-nitrosoglutathione: implication for stroke therapy. BMC Neurosci 2015; 16:42. [PMID: 26174015 PMCID: PMC4502912 DOI: 10.1186/s12868-015-0179-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 07/06/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Stroke immediately sets into motion sustained excitotoxicity and calcium dysregulation, causing aberrant activity in neuronal nitric oxide synthase (nNOS) and an imbalance in the levels of nitric oxide (NO). Drugs targeting nNOS-originated toxicity may therefore reduce stroke-induced damage. Recently, we observed that a redox-modulating agent of the NO metabolome, S-nitrosoglutathione (GSNO), confers neurovascular protection by reducing the levels of peroxynitrite, a product of aberrant NOS activity. We therefore investigated whether GSNO-mediated neuroprotection and improved neurological functions depend on blocking nNOS/peroxynitrite-associated injurious mechanisms using a rat model of cerebral ischemia reperfusion (IR). RESULTS IR increased the activity of nNOS, the levels of neuronal peroxynitrite and phosphorylation at Ser(1412) of nNOS. GSNO treatment of IR animals decreased IR-activated nNOS activity and neuronal peroxynitrite levels by reducing nNOS phosphorylation at Ser(1412). The Ser(1412) phosphorylation is associated with increased nNOS activity. Supporting the notion that nNOS activity and peroxynitrite are deleterious following IR, inhibition of nNOS by its inhibitor 7-nitroindazole or reducing peroxynitrite by its scavenger FeTPPS decreased IR injury. GSNO also decreased the activation of AMP Kinase (AMPK) and its upstream kinase LKB1, both of which were activated in IR brain. AMPK has been implicated in nNOS activation via Ser(1412) phosphorylation. To determine whether AMPK activation is deleterious in the acute phase of IR, we treated animals after IR with AICAR (an AMPK activator) and compound c (an AMPK inhibitor). While AICAR potentiated, compound c reduced the IR injury. CONCLUSIONS Taken together, these results indicate an injurious nNOS/peroxynitrite/AMPK cycle following stroke, and GSNO treatment of IR inhibits this vicious cycle, resulting in neuroprotection and improved neurological function. GSNO is a natural component of the human body, and its exogenous administration to humans is not associated with any known side effects. Currently, the FDA-approved thrombolytic therapy suffers from a lack of neuronal protective activity. Because GSNO provides neuroprotection by ameliorating stroke's initial and causative injuries, it is a candidate of translational value for stroke therapy.
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Affiliation(s)
- Mushfiquddin Khan
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC, 29425, USA.
| | - Tajinder S Dhammu
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC, 29425, USA.
| | - Fumiyo Matsuda
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC, 29425, USA. .,School of Health Science, Kagoshima University, Kagoshima, Japan.
| | - Avtar K Singh
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA. .,Ralph H. Johnson VA Medical Center, Charleston, SC, USA.
| | - Inderjit Singh
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC, 29425, USA.
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11
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Jendzjowsky NG, Just TP, Jones KE, DeLorey DS. Acute tetrahydrobiopterin supplementation attenuates sympathetic vasoconstrictor responsiveness in resting and contracting skeletal muscle of healthy rats. Physiol Rep 2014; 2:2/10/e12164. [PMID: 25318748 PMCID: PMC4254091 DOI: 10.14814/phy2.12164] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Tetrahydrobiopterin (BH4) is an essential cofactor for the production of nitric oxide (NO) and supplementation with BH4 improves NO‐dependent vasodilation. NO also reduces sympathetic vasoconstrictor responsiveness in resting and contracting skeletal muscle. Thus, we hypothesized that supplementation with BH4 would blunt sympathetic vasoconstrictor responsiveness in resting and contracting skeletal muscle. Sprague‐Dawley rats (n = 15, 399 ± 57 g) were anesthetized and instrumented with an indwelling brachial artery catheter, femoral artery flow probe, and a stimulating electrode on the lumbar sympathetic chain. Triceps surae muscles were stimulated to contract rhythmically at 30% and 60% of maximal contractile force (MCF). The percentage change of femoral vascular conductance (%FVC) in response to sympathetic stimulations delivered at 2 and 5 Hz was determined at rest and during muscle contraction in control and acute BH4 supplementation (20 mg·kg−1 + 10 mg·kg−1·h−1, IA) conditions. BH4 reduced (P < 0.05) the vasoconstrictor response to sympathetic stimulation (i.e., decrease in FVC) at rest (Control: 2 Hz: −28 ± 5%FVC; 5 Hz: −45 ± 5%; BH4: 2 Hz: −17 ± 4%FVC; 5 Hz: −34 ± 7%FVC) and during muscular contraction at 30% MCF (Control: 2 Hz: −14 ± 6%FVC; 5 Hz: −28 ± 11%; BH4: 2 Hz: −6 ± 6%FVC; 5 Hz: −16 ± 10%) and 60% MCF (Control: 2 Hz: −7 ± 3%FVC; 5 Hz: −16 ± 6%FVC; BH4: 2 Hz: −2 ± 3%FVC; 5 Hz: −11 ± 6%FVC). These data are consistent with our hypothesis that acute BH4 supplementation decreases sympathetic vasoconstrictor responsiveness in resting and contracting skeletal muscle. Tetrahydrobiopterin (BH4) is an essential cofactor for the production of nitric oxide (NO) and NO reduces sympathetic vasoconstrictor responsiveness in the skeletal muscle vascular bed. Thus, we hypothesized that supplementation with BH4 would blunt sympathetic vasoconstrictor responsiveness. The data demonstrate that acute BH4 supplementation decreases sympathetic vasoconstrictor responsiveness in resting and contracting skeletal muscle.
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Affiliation(s)
- Nicholas G Jendzjowsky
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Timothy P Just
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Kelvin E Jones
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Darren S DeLorey
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
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12
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Abstract
In the beating heart, mechanical stretch triggers the production of reactive oxygen or nitrogen species that target Ca(2+)-signaling proteins. Termed mechano-chemo transduction, this pathway "tunes" the calcium release machinery in the healthy heart; when dysregulated, it contributes to disease. In this issue of Science Signaling, Jian et al. used a "cell-in-gel" method to show that contractions in healthy heart cells elicit a steep, viscosity-dependent increase in mechano-chemo transduction in which nitric oxide synthase (NOS), NADPH oxidase 2 (Nox2), and Ca(2+)/calmodulin-dependent kinase II (CaMKII) contribute. These authors provide evidence for a role of neuronal NOS (nNOS) over endothelial NOS; they supported their findings with super-resolution microscopy, which localized nNOS nearest to the Ca(2+) release sites. In a disease model, signaling through nNOS and CaMKII rather than through Nox2 was enhanced, supporting the independent mechano-activation of these enzymes. The coupling of these quantitative approaches will provide a new understanding of mechano-chemo transduction.
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Affiliation(s)
- Benjamin L Prosser
- 1Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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13
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Tang L, Wang H, Ziolo MT. Targeting NOS as a therapeutic approach for heart failure. Pharmacol Ther 2013; 142:306-15. [PMID: 24380841 DOI: 10.1016/j.pharmthera.2013.12.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 11/19/2013] [Indexed: 02/07/2023]
Abstract
Nitric oxide is a key signaling molecule in the heart and is produced endogenously by three isoforms of nitric oxide synthase, neuronal NOS (NOS1), endothelial NOS (NOS3), and inducible NOS (NOS2). Nitric oxide signals via cGMP-dependent or independent pathways to modulate downstream proteins via specific post translational modifications (i.e. cGMP-dependent protein kinase phosphorylation, S-nitrosylation, etc.). Dysfunction of NOS (i.e. altered expression, location, coupling, activity, etc.) exists in various cardiac disease conditions, such as heart failure, contributing to the contractile dysfunction, adverse remodeling, and hypertrophy. This review will focus on the signaling pathways of each NOS isoform during health and disease, and discuss current and potential therapeutic approaches targeting nitric oxide signaling to treat heart disease.
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Affiliation(s)
- Lifei Tang
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, USA
| | - Honglan Wang
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, USA
| | - Mark T Ziolo
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, USA.
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14
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Stobart JL, Anderson CM. Multifunctional role of astrocytes as gatekeepers of neuronal energy supply. Front Cell Neurosci 2013; 7:38. [PMID: 23596393 PMCID: PMC3622037 DOI: 10.3389/fncel.2013.00038] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 03/26/2013] [Indexed: 01/01/2023] Open
Abstract
Dynamic adjustments to neuronal energy supply in response to synaptic activity are critical for neuronal function. Glial cells known as astrocytes have processes that ensheath most central synapses and express G-protein-coupled neurotransmitter receptors and transporters that respond to neuronal activity. Astrocytes also release substrates for neuronal oxidative phosphorylation and have processes that terminate on the surface of brain arterioles and can influence vascular smooth muscle tone and local blood flow. Membrane receptor or transporter-mediated effects of glutamate represent a convergence point of astrocyte influence on neuronal bioenergetics. Astrocytic glutamate uptake drives glycolysis and subsequent shuttling of lactate from astrocytes to neurons for oxidative metabolism. Astrocytes also convert synaptically reclaimed glutamate to glutamine, which is returned to neurons for glutamate salvage or oxidation. Finally, astrocytes store brain energy currency in the form of glycogen, which can be mobilized to produce lactate for neuronal oxidative phosphorylation in response to glutamatergic neurotransmission. These mechanisms couple synaptically driven astrocytic responses to glutamate with release of energy substrates back to neurons to match demand with supply. In addition, astrocytes directly influence the tone of penetrating brain arterioles in response to glutamatergic neurotransmission, coordinating dynamic regulation of local blood flow. We will describe the role of astrocytes in neurometabolic and neurovascular coupling in detail and discuss, in turn, how astrocyte dysfunction may contribute to neuronal bioenergetic deficit and neurodegeneration. Understanding the role of astrocytes as a hub for neurometabolic and neurovascular coupling mechanisms is a critical underpinning for therapeutic development in a broad range of neurodegenerative disorders characterized by chronic generalized brain ischemia and brain microvascular dysfunction.
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Affiliation(s)
- Jillian L Stobart
- Division of Neurodegenerative Disorders, Department of Pharmacology and Therapeutics, St. Boniface Hospital Research, University of Manitoba Winnipeg, MB, Canada ; Department of Nuclear Medicine, Institute of Pharmacology and Toxicology, University of Zürich Zürich, Switzerland
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15
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Carnicer R, Crabtree MJ, Sivakumaran V, Casadei B, Kass DA. Nitric oxide synthases in heart failure. Antioxid Redox Signal 2013; 18:1078-99. [PMID: 22871241 PMCID: PMC3567782 DOI: 10.1089/ars.2012.4824] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 08/07/2012] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE The regulation of myocardial function by constitutive nitric oxide synthases (NOS) is important for the maintenance of myocardial Ca(2+) homeostasis, relaxation and distensibility, and protection from arrhythmia and abnormal stress stimuli. However, sustained insults such as diabetes, hypertension, hemodynamic overload, and atrial fibrillation lead to dysfunctional NOS activity with superoxide produced instead of NO and worse pathophysiology. RECENT ADVANCES Major strides in understanding the role of normal and abnormal constitutive NOS in the heart have revealed molecular targets by which NO modulates myocyte function and morphology, the role and nature of post-translational modifications of NOS, and factors controlling nitroso-redox balance. Localized and differential signaling from NOS1 (neuronal) versus NOS3 (endothelial) isoforms are being identified, as are methods to restore NOS function in heart disease. CRITICAL ISSUES Abnormal NOS signaling plays a key role in many cardiac disorders, while targeted modulation may potentially reverse this pathogenic source of oxidative stress. FUTURE DIRECTIONS Improvements in the clinical translation of potent modulators of NOS function/dysfunction may ultimately provide a powerful new treatment for many hearts diseases that are fueled by nitroso-redox imbalance.
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Affiliation(s)
- Ricardo Carnicer
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Mark J. Crabtree
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Vidhya Sivakumaran
- Division of Cardiology, Department of Medicine, Johns Hopkins University Medical Institutions, Baltimore, Maryland
| | - Barbara Casadei
- Department of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - David A. Kass
- Division of Cardiology, Department of Medicine, Johns Hopkins University Medical Institutions, Baltimore, Maryland
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16
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Walkowska A, Sadowski J, Kompanowska-Jezierska E. Oxidative stress and neuronal NOS activity: putative determinants of rapid blood pressure increase after renal denervation in anesthetized rats. Physiol Res 2013; 62:257-66. [PMID: 23489187 DOI: 10.33549/physiolres.932468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Long-term effects of renal denervation (DNX) commonly include a decrease in blood pressure (BP), observed in both normotensive animals and various models of hypertension. On the other hand, short term BP responses vary. We examined how post-DNX increase in BP observed in this study depends on baseline metabolic and functional status of animals, with a special interest for the role of oxidative stress. Anesthetized Wistar rats on standard (STD), low-sodium (LS) or high-sodium (HS) diet were used, untreated or pre-treated with tempol, a superoxide scavenger, or N(omega)-propyl-L-arginine (L-NPA), an inhibitor of neuronal NOS (nNOS). Early BP and renal hemodynamic responses were examined to right- and then left-side DNX performed using an own relatively non-invasive technique. Left kidney cortical, outer- and inner-medullary blood flows (CBF, OMBF, IMBF) were continuously recorded as laser-Doppler fluxes. Sequential denervations significantly increased BP to final 19 %, 12 %, and 6 % above control level in HS, LS, and STD groups, respectively. CBF, a measure of total renal perfusion, increased in LS and STD but not in HS rats. Tempol pretreatment prevented the post-denervation BP increase on each diet. Selective inhibition of nNOS prevented BP increase in STD and HS groups, a modest increase persisted in LS rats. We propose that enhanced afferent impulsation from intrarenal chemoreceptors related to oxidative stress in the kidney was the background for acute BP increase after DNX. The response was triggered by a release of brain sympatho-excitatory centers from inhibition by renal afferents, this was followed by widespread sympathetic cardiovascular stimulation.
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Affiliation(s)
- A Walkowska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland.
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17
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Kohr MJ, Roof SR, Zweier JL, Ziolo MT. Modulation of myocardial contraction by peroxynitrite. Front Physiol 2012; 3:468. [PMID: 23248603 PMCID: PMC3520483 DOI: 10.3389/fphys.2012.00468] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 11/26/2012] [Indexed: 12/18/2022] Open
Abstract
Peroxynitrite is a potent oxidant that is quickly emerging as a crucial modulator of myocardial function. This review will focus on the regulation of myocardial contraction by peroxynitrite during health and disease, with a specific emphasis on cardiomyocyte Ca2+ handling, proposed signaling pathways, and protein end-targets.
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Affiliation(s)
- Mark J Kohr
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Columbus, OH, USA ; Division of Cardiovascular Pathology, Department of Pathology, Johns Hopkins University Baltimore, MD, USA
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18
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Hirai DM, Copp SW, Holdsworth CT, Ferguson SK, Musch TI, Poole DC. Effects of neuronal nitric oxide synthase inhibition on microvascular and contractile function in skeletal muscle of aged rats. Am J Physiol Heart Circ Physiol 2012; 303:H1076-84. [PMID: 22923618 DOI: 10.1152/ajpheart.00477.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Advanced age is associated with derangements in skeletal muscle microvascular function during the transition from rest to contractions. We tested the hypothesis that, contrary to what was reported previously in young rats, selective neuronal nitric oxide (NO) synthase (nNOS) inhibition would result in attenuated or absent alterations in skeletal muscle microvascular oxygenation (Po(2)(mv)), which reflects the matching between muscle O(2) delivery and utilization, following the onset of contractions in old rats. Spinotrapezius muscle blood flow (radiolabeled microspheres), Po(2)(mv) (phosphorescence quenching), O(2) utilization (Vo(2); Fick calculation), and submaximal force production were measured at rest and following the onset of contractions in anesthetized old male Fischer 344 × Brown Norway rats (27 to 28 mo) pre- and postselective nNOS inhibition (2.1 μmol/kg S-methyl-l-thiocitrulline; SMTC). At rest, SMTC had no effects on muscle blood flow (P > 0.05) but reduced Vo(2) by ∼23% (P < 0.05), which elevated basal Po(2)(mv) by ∼18% (P < 0.05). During contractions, steady-state muscle blood flow, Vo(2), Po(2)(mv), and force production were not altered after SMTC (P > 0.05 for all). The overall Po(2)(mv) dynamics following onset of contractions was also unaffected by SMTC (mean response time: pre, 19.7 ± 1.5; and post, 20.0 ± 2.0 s; P > 0.05). These results indicate that the locus of nNOS-derived NO control in skeletal muscle depends on age and metabolic rate (i.e., rest vs. contractions). Alterations in nNOS-mediated regulation of contracting skeletal muscle microvascular function with aging may contribute to poor exercise capacity in this population.
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Affiliation(s)
- Daniel M Hirai
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506-5802, USA
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Lekontseva O, Jiang Y, Schleppe C, Davidge ST. Altered neuronal nitric oxide synthase in the aging vascular system: implications for estrogens therapy. Endocrinology 2012; 153:3940-8. [PMID: 22700772 DOI: 10.1210/en.2012-1071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ovarian dysfunction at any age is associated with increased cardiovascular risk in women; however, therapeutic effects of exogenous estrogens are age dependent. Estradiol (E2) activates neuronal nitric oxide synthase (nNOS) in vascular cells. Because nNOS is prone to uncoupling under unfavorable biochemical conditions (as seen in aging), E2 stimulation of nNOS may lack vascular benefits in aging. Small mesenteric arteries were isolated from female Sprague Dawley rats, 3 or 12 months old, who were ovariectomized (Ovx) and treated with placebo or E2 for 4 wk. Vascular relaxation to exogenous E2 (0.001-100 μmol/liter) ± selective nNOS inhibitor (N-propyl-l-arginine, 2 μmol/liter) or pan-NOS inhibitor [Nω-nitro-l-arginine methyl ester (l-NAME), 100 μmol/liter] was examined on wire myograph. NOS expression was measured by Western blotting in thoracic aortas, in which superoxide generation was detected as dihydroethidium (DHE) fluorescence. E2 relaxations were impaired in Ovx conditions. E2 treatment (4 wk) normalized vascular function in young rats only. Both l-N-propyl-l-arginine and l-NAME blunted E2 relaxation in young controls, but only l-NAME did so in aging controls. NOS inhibition had no effect on acute E2 relaxation in Ovx rats, regardless of age or treatment. nNOS expression was similar in all animal groups. However, nNOS inhibition increased DHE fluorescence in young controls, whereas it reduced it in aging or Ovx animals. In E2-treated animals of either age, superoxide production was NOS independent. In conclusion, nNOS contributed to vascular relaxation in young, but not aging rats, where its enzymatic function shifted toward superoxide production. Thus, nNOS dysfunction may explain a mechanism of impaired E2 signaling in aging conditions.
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Affiliation(s)
- Olga Lekontseva
- Department of Physiology, Women and Children’s Health Research Institute, Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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20
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Protein S-nitrosylation and denitrosylation in the mouse spinal cord upon injury of the sciatic nerve. J Proteomics 2012; 75:3987-4004. [DOI: 10.1016/j.jprot.2012.05.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/25/2012] [Accepted: 05/04/2012] [Indexed: 01/05/2023]
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21
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Biondi R, Ambrosio G, De Pascali F, Tritto I, Capodicasa E, Druhan LJ, Hemann C, Zweier JL. HPLC analysis of tetrahydrobiopterin and its pteridine derivatives using sequential electrochemical and fluorimetric detection: application to tetrahydrobiopterin autoxidation and chemical oxidation. Arch Biochem Biophys 2012; 520:7-16. [PMID: 22286026 PMCID: PMC3307828 DOI: 10.1016/j.abb.2012.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/03/2012] [Accepted: 01/10/2012] [Indexed: 02/07/2023]
Abstract
Tetrahydrobiopterin (BH(4)) is an essential cofactor of endothelial nitric oxide (NO) synthase and when depleted, endothelial dysfunction results with decreased production of NO. BH(4) is also an anti-oxidant being a good "scavenger" of oxidative species. NADPH oxidase, xanthine oxidase, and mitochondrial enzymes producing reactive oxygen species (ROS) can induce elevated oxidant stress and cause BH(4) oxidation and subsequent decrease in NO production and bioavailability. In order to define the process of ROS-mediated BH(4) degradation, a sensitive method for monitoring pteridine redox-state changes is required. Considering that the conventional fluorescence method is an indirect method requiring conversion of all pteridines to oxidized forms, it would be beneficial to use a rapid quantitative assay for the individual detection of BH(4) and its related pteridine metabolites. To study, in detail, the BH(4) oxidative pathways, a rapid direct sensitive HPLC assay of BH(4) and its pteridine derivatives was adapted using sequential electrochemical and fluorimetric detection. We examined BH(4) autoxidation, hydrogen peroxide- and superoxide-driven oxidation, and Fenton reaction hydroxyl radical-driven BH(4) transformation. We demonstrate that the formation of the primary two-electron oxidation product, dihydrobiopterin (BH(2)), predominates with oxygen-induced BH(4) autoxidation and superoxide-catalyzed oxidation, while the irreversible metabolites, pterin and dihydroxanthopterin (XH(2)), are largely produced during hydroxyl radical-driven BH(4) oxidation.
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Affiliation(s)
- Roberto Biondi
- Division of Cardiology, University of Perugia School of Medicine, 06100 Perugia
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, Ohio State University, Columbus, OH 43210
- Azienda Ospedaliera “S.Maria” Terni
- Dipartimento di Medicina Clinica Sperimentale, University of Perugia School of Medicine, 06100 Perugia
| | - Giuseppe Ambrosio
- Division of Cardiology, University of Perugia School of Medicine, 06100 Perugia
- Dipartimento di Medicina Clinica Sperimentale, University of Perugia School of Medicine, 06100 Perugia
| | - Francesco De Pascali
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, Ohio State University, Columbus, OH 43210
| | - Isabella Tritto
- Division of Cardiology, University of Perugia School of Medicine, 06100 Perugia
- Dipartimento di Medicina Clinica Sperimentale, University of Perugia School of Medicine, 06100 Perugia
| | - Enrico Capodicasa
- Dipartimento di Medicina Clinica Sperimentale, University of Perugia School of Medicine, 06100 Perugia
| | - Lawrence J. Druhan
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, Ohio State University, Columbus, OH 43210
- Department of Anesthesiology, College of Medicine, Ohio State University, Columbus, OH 43210
| | - Craig Hemann
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, Ohio State University, Columbus, OH 43210
| | - Jay L. Zweier
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, Ohio State University, Columbus, OH 43210
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Sezen SF, Lagoda G, Burnett AL. Neuronal nitric oxide signaling regulates erection recovery after cavernous nerve injury. J Urol 2011; 187:757-63. [PMID: 22177198 DOI: 10.1016/j.juro.2011.09.146] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Indexed: 12/31/2022]
Abstract
PURPOSE Nitric oxide is the major neuronal mediator of penile erection but its role in erectile function status after cavernous nerve injury is uncertain. We determined the function of neuronal nitric oxide signaling in the pathobiology of erectile function recovery after partial cavernous nerve injury using genetic and pharmacological mouse experimental paradigms. MATERIALS AND METHODS Erectile function was evaluated in 5 to 7 wild-type and neuronal nitric oxide synthase-α knockout mice per group 1, 3 and 7 days after unilateral crush or sham injury, at day 7 in wild-type mice treated with the nitric oxide synthase inhibitor L-NAME (l-nitro arginine methyl ester) (Sigma-Aldrich®) at baseline and for 6 days after unilateral crush injury. Apoptosis in the penis was evaluated by Western blot analysis of p-Akt-S473, 3-nitrotyrosine and caspase-3 after bilateral crush injury. RESULTS Intracavernous pressure was significantly decreased at 1, 3 and 7 days in wild-type mice but only at day 1 in knockout mice after unilateral crush injury compared with sham treatment values (p <0.05). L-NAME treated wild-type mice had improved erectile function compared with the vehicle treated group at day 7 after unilateral crush injury (p <0.05). In penes p-Akt-S473 was significantly decreased in vehicle treated (p <0.05) but not in L-NAME treated wild-type mice. In penes 3-nitrotyrosine was significantly decreased in L-NAME treated wild-type and vehicle treated knockout mice (p <0.05). Caspase-3 in penes was significantly increased in vehicle treated (p <0.05) but not in L-NAME treated wild-type mice and vehicle treated knockout mice. CONCLUSIONS Neuronal nitric oxide signaling regulates erectile function recovery early after partial cavernous nerve injury, exerting an inhibitory role via the induction of apoptotic change in penile tissue. Therapeutic strategies to improve erectile function recovery after radical prostatectomy may consider targeting pathogenic sites of nitric oxide neurobiology.
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Affiliation(s)
- Sena F Sezen
- Department of Urology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
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23
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Zweier JL, Chen CA, Druhan LJ. S-glutathionylation reshapes our understanding of endothelial nitric oxide synthase uncoupling and nitric oxide/reactive oxygen species-mediated signaling. Antioxid Redox Signal 2011; 14:1769-75. [PMID: 21261471 PMCID: PMC3078498 DOI: 10.1089/ars.2011.3904] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Oxidative stress has been shown to convert endothelial nitric oxide synthase (eNOS) from an NO-producing enzyme to an enzyme that generates superoxide, a process termed NOS uncoupling. This uncoupling of eNOS converts it to function as an NADPH oxidase with superoxide and hydrogen peroxide generation. eNOS uncoupling has been associated with many pathophysiologic conditions, such as heart failure, ischemia/reperfusion injury, hypertension, atherosclerosis, and diabetes. The mechanisms implicated in the uncoupling of eNOS include oxidation of the critical NOS cofactor tetrahydrobiopterin, depletion of L-arginine, and accumulation of methylarginines. All of these prior mechanisms of eNOS-derived reactive oxygen species formation occur primarily at the heme of the oxygenase domain and are blocked by heme blockers or the NOS inhibitor N-nitro-L-arginine methylester. Recently, we have identified another unique mechanism of redox regulation of eNOS through S-glutathionylation that was shown to be important in cell signaling and vascular disease. Herein, we briefly review the mechanisms of eNOS uncoupling as well as their interrelationships and the evidence for their importance in disease.
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Affiliation(s)
- Jay L. Zweier
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Chun-An Chen
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Lawrence J. Druhan
- Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio
- Department of Anesthesiology, College of Medicine, The Ohio State University, Columbus, Ohio
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Slyvka Y, Wang Z, Yee J, Inman SR, Nowak FV. Antioxidant diet, gender and age affect renal expression of nitric oxide synthases in obese diabetic rats. Nitric Oxide 2011; 24:50-60. [DOI: 10.1016/j.niox.2010.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 08/28/2010] [Accepted: 11/15/2010] [Indexed: 01/07/2023]
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Abstract
Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now recognized that neurotransmitter-mediated signalling has a key role in regulating cerebral blood flow, that much of this control is mediated by astrocytes, that oxygen modulates blood flow regulation, and that blood flow may be controlled by capillaries as well as by arterioles. These conceptual shifts in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches.
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GANGULA PRR, MUKHOPADHYAY S, PASRICHA PJ, RAVELLA K. Sepiapterin reverses the changes in gastric nNOS dimerization and function in diabetic gastroparesis. Neurogastroenterol Motil 2010; 22:1325-31, e351-2. [PMID: 20731778 PMCID: PMC3072796 DOI: 10.1111/j.1365-2982.2010.01588.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND We have demonstrated previously that in vivo supplementation of tetrahydrobiopterin (BH₄); a co-factor for neuronal nitric oxide synthase (nNOS) significantly restored delayed gastric emptying and attenuated nitrergic relaxation in diabetic rat. In this study, we have investigated whether supplementation of sepiapterin (SEP), a precursor for BH₄ biosynthesis via salvage pathway restores gastric emptying and nitrergic system in female diabetic rats. METHODS Diabetic rats (streptozotocin-induced) were supplemented with BH₄ or SEP (20 mg kg⁻¹ body weight). Gastric nitrergic relaxation in the presence or absence of high glucose and SEP were measured by electric field stimulation. Gastric muscular strips from healthy or diabetic female rats were incubated in the presence or absence of high glucose, SEP and/or methotrexate (MTX). Nitric oxide release was measured colorimetrically by NO assay kit. The expression of nNOSα and dimerization was detected by Western blot. KEY RESULTS In vitro studies on gastric muscular tissues showed that MTX, an inhibitor of BH₄ synthesis via salvage pathway, significantly decreased NO release. In vivo treatment with MTX reduced both gastric nitrergic relaxation and nNOSα dimerization. Supplementation of SEP significantly attenuated delayed gastric emptying in diabetic rats. In addition, SEP supplementation restored impaired nitrergic relaxation, gastric nNOSα protein expression, and dimerization in diabetic rats. CONCLUSIONS & INFERENCES The above data suggests that supplementation of SEP accelerated gastric emptying and attenuated reduced gastric nNOSα expression, and dimerization. Therefore, SEP supplementation is a potential therapeutic option for female patients of diabetic gastroparesis.
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Affiliation(s)
- P. R. R. GANGULA
- Department of physiology, Center for Women’s Health Research, Meharry Medical College, Nashville, TN, USA
| | - S. MUKHOPADHYAY
- Department of physiology, Center for Women’s Health Research, Meharry Medical College, Nashville, TN, USA
| | - P. J. PASRICHA
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA, USA
| | - K. RAVELLA
- Department of physiology, Center for Women’s Health Research, Meharry Medical College, Nashville, TN, USA
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Abstract
Tetrahydrobiopterin (BH4) is a multifunctional cofactor of aromatic amino acid hydroxylases and nitric oxide synthase (NOS) as well as an intracellular antioxidant in animals. Through regulation of NOS activity BH4 plays a pivotal role not only in a variety of normal cellular functions but also in the pathogenesis of cardiovascular and neurodegenerative diseases, which develop under oxidative stress conditions. It appears that a balanced interplay between BH4 and NOS is crucial for cellular fate. If cellular BH4 homeostasis maintained by BH4 synthesis and regeneration fails to cope with increased oxidative stress, NOS is uncoupled to generate superoxide rather than NO and, in turn, exacerbates impaired BH4 homeostasis, thereby leading to cell death. The fundamental biochemical events involved in the BH4-NOS interplay are essentially the same, as revealed in mammalian endothelial, cardiac, and neuronal cells. This review summarizes information on the cellular BH4 homeostasis in mammals, focusing on its regulation under normal and oxidative stress conditions.
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Chen W, Druhan LJ, Chen CA, Hemann C, Chen YR, Berka V, Tsai AL, Zweier JL. Peroxynitrite induces destruction of the tetrahydrobiopterin and heme in endothelial nitric oxide synthase: transition from reversible to irreversible enzyme inhibition. Biochemistry 2010; 49:3129-37. [PMID: 20184376 PMCID: PMC2851177 DOI: 10.1021/bi9016632] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Endothelial nitric oxide synthase (eNOS) is an important regulator of vascular and cardiac function. Peroxynitrite (ONOO(-)) inactivates eNOS, but questions remain regarding the mechanisms of this process. It has been reported that inactivation is due to oxidation of the eNOS zinc-thiolate cluster, rather than the cofactor tetrahydrobiopterin (BH(4)); however, this remains highly controversial. Therefore, we investigated the mechanisms of ONOO(-)-induced eNOS dysfunction and their dose dependence. Exposure of human eNOS to ONOO(-) resulted in a dose-dependent loss of activity with a marked destabilization of the eNOS dimer. HPLC analysis indicated that both free and eNOS-bound BH(4) were oxidized during exposure to ONOO(-); however, full oxidation of protein-bound biopterin required higher ONOO(-) levels. Additionally, ONOO(-) triggered changes in the UV/visible spectrum and heme content of the enzyme. Preincubation of eNOS with BH(4) decreased dimer destabilization and heme alteration. Addition of BH(4) to the ONOO(-)-destabilized eNOS dimer only partially rescued enzyme function. In contrast to ONOO(-) treatment, incubation with the zinc chelator TPEN with removal of enzyme-bound zinc did not change the eNOS activity or stability of the SDS-resistant eNOS dimer, demonstrating that the dimer stabilization induced by BH(4) does not require zinc occupancy of the zinc-thiolate cluster. While ONOO(-) treatment was observed to induce loss of Zn binding, this cannot account for the loss of enzyme activity. Therefore, ONOO(-)-induced eNOS inactivation is primarily due to oxidation of BH(4) and irreversible destruction of the heme/heme center.
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Affiliation(s)
- Weiguo Chen
- Davis Heart & Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Lawrence J. Druhan
- Davis Heart & Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Chun-An Chen
- Davis Heart & Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Craig Hemann
- Davis Heart & Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Yeong-Renn Chen
- Davis Heart & Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio 43210
| | - Vladimir Berka
- Division of Hematology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Ah-Lim Tsai
- Division of Hematology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Jay L. Zweier
- Davis Heart & Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, Ohio 43210
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29
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Sun J, Druhan LJ, Zweier JL. Reactive oxygen and nitrogen species regulate inducible nitric oxide synthase function shifting the balance of nitric oxide and superoxide production. Arch Biochem Biophys 2010; 494:130-7. [PMID: 19932078 PMCID: PMC4073618 DOI: 10.1016/j.abb.2009.11.019] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 11/17/2009] [Indexed: 01/30/2023]
Abstract
Inducible NOS (iNOS) is induced in diseases associated with inflammation and oxidative stress, and questions remain regarding its regulation. We demonstrate that reactive oxygen/nitrogen species (ROS/RNS) dose-dependently regulate iNOS function. Tetrahydrobiopterin (BH4)-replete iNOS was exposed to increasing concentrations of ROS/RNS and activity was measured with and without subsequent BH4 addition. Peroxynitrite (ONOO(-)) produced the greatest change in NO generation rate, approximately 95% decrease, and BH4 only partially restored this loss of activity. Superoxide (O2(.-)) greatly decreased NO generation, however, BH4 addition restored this activity. Hydroxyl radical ((.)OH) mildly decreases NO generation in a BH4-dependent manner. iNOS was resistant to H2O2 with only slightly decreased NO generation with up to millimolar concentrations. In contrast to the inhibition of NO generation, ROS enhanced O2(.-) production from iNOS, while ONOO(-) had the opposite effect. Thus, ROS promote reversible iNOS uncoupling, while ONOO(-) induces irreversible enzyme inactivation and decreases both NO and O2(.-) production.
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Affiliation(s)
- Jian Sun
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, College of Medicine, Columbus, OH 43210, USA
| | - Lawrence J. Druhan
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, College of Medicine, Columbus, OH 43210, USA
| | - Jay L. Zweier
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, College of Medicine, Columbus, OH 43210, USA
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30
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Silberman GA, Fan THM, Liu H, Jiao Z, Xiao HD, Lovelock JD, Boulden BM, Widder J, Fredd S, Bernstein KE, Wolska BM, Dikalov S, Harrison DG, Dudley SC. Uncoupled cardiac nitric oxide synthase mediates diastolic dysfunction. Circulation 2010; 121:519-28. [PMID: 20083682 PMCID: PMC2819317 DOI: 10.1161/circulationaha.109.883777] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Heart failure with preserved ejection fraction is 1 consequence of hypertension and is caused by impaired cardiac diastolic relaxation. Nitric oxide (NO) is a known modulator of cardiac relaxation. Hypertension can lead to a reduction in vascular NO, in part because NO synthase (NOS) becomes uncoupled when oxidative depletion of its cofactor tetrahydrobiopterin (BH(4)) occurs. Similar events may occur in the heart that lead to uncoupled NOS and diastolic dysfunction. METHODS AND RESULTS In a hypertensive mouse model, diastolic dysfunction was accompanied by cardiac oxidation, a reduction in cardiac BH(4), and uncoupled NOS. Compared with sham-operated animals, male mice with unilateral nephrectomy, with subcutaneous implantation of a controlled-release deoxycorticosterone acetate pellet, and given 1% saline to drink were mildly hypertensive and had diastolic dysfunction in the absence of systolic dysfunction or cardiac hypertrophy. The hypertensive mouse hearts showed increased oxidized biopterins, NOS-dependent superoxide production, reduced NO production, and dephosphorylated phospholamban. Feeding hypertensive mice BH(4) (5 mg/d), but not treating with hydralazine or tetrahydroneopterin, improved cardiac BH(4) stores, phosphorylated phospholamban levels, and diastolic dysfunction. Isolated cardiomyocyte experiments revealed impaired relaxation that was normalized with short-term BH(4) treatment. Targeted cardiac overexpression of angiotensin-converting enzyme also resulted in cardiac oxidation, NOS uncoupling, and diastolic dysfunction in the absence of hypertension. CONCLUSIONS Cardiac oxidation, independently of vascular changes, can lead to uncoupled cardiac NOS and diastolic dysfunction. BH(4) may represent a possible treatment for diastolic dysfunction.
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Affiliation(s)
- Gad A. Silberman
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
| | - Tai-Hwang M. Fan
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
- Atlanta VA Medical Center, Atlanta, GA
| | - Hong Liu
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
- Section of Cardiology, University of Illinois at Chicago, Chicago, IL and the Jesse Brown VA Medical Center, Chicago IL
| | - Zhe Jiao
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
- Section of Cardiology, University of Illinois at Chicago, Chicago, IL and the Jesse Brown VA Medical Center, Chicago IL
| | - Hong D. Xiao
- Department of Pathology, Massachusetts General Hospital, Boston, MA
| | - Joshua D. Lovelock
- Section of Cardiology, University of Illinois at Chicago, Chicago, IL and the Jesse Brown VA Medical Center, Chicago IL
| | - Beth M. Boulden
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
| | - Julian Widder
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
| | - Scott Fredd
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
| | | | - Beata M. Wolska
- Section of Cardiology, University of Illinois at Chicago, Chicago, IL and the Jesse Brown VA Medical Center, Chicago IL
| | - Sergey Dikalov
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
| | - David G. Harrison
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
- Atlanta VA Medical Center, Atlanta, GA
| | - Samuel C. Dudley
- Department of Medicine (Division of Cardiology), Emory University School of Medicine, Atlanta, GA
- Atlanta VA Medical Center, Atlanta, GA
- Section of Cardiology, University of Illinois at Chicago, Chicago, IL and the Jesse Brown VA Medical Center, Chicago IL
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Trujillo M, Alvarez B, Souza JM, Romero N, Castro L, Thomson L, Radi R. Mechanisms and Biological Consequences of Peroxynitrite-Dependent Protein Oxidation and Nitration. Nitric Oxide 2010. [DOI: 10.1016/b978-0-12-373866-0.00003-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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32
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Bréard M, Grillon C. Serotonin binds to purified neuronal nitric oxide synthase: a possible explanation for ROS production induced by 5HT in the presence of nNOS. Free Radic Res 2009; 43:206-13. [PMID: 19191108 DOI: 10.1080/10715760802676662] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Serotonin (5HT) was shown to induce in vitro the production of ROS in the presence of neuronal nitric oxide synthase (nNOS) in addition to the basal NO(+) formation. With the aim of understanding this mechanism, this study investigated the potential binding of 5HT to nNOS. By using [(3)H]5HT, it is reported here that 5HT binds to nNOS, but only when the enzyme is active and in a superoxide-dependent manner. This binding is prevented by DPI but not by L-NAME. The formation of 5HT-nNOS complex was shown to be very well correlated with the production of ROS by 5HT in the presence of nNOS. A mechanism involving nNOS only in its initial step is proposed to explain both the formation of 5HT-nNOS complex and the production of ROS observed in the presence of nNOS and 5HT.
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Affiliation(s)
- Maud Bréard
- Institut de Chimie des Substances Naturelles, Centre National de la Recherche Scientifique, Gif sur Yvette, France
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33
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Hollenberg SM, Cinel I. Bench-to-bedside review: nitric oxide in critical illness--update 2008. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:218. [PMID: 19664175 PMCID: PMC2750127 DOI: 10.1186/cc7706] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nitric oxide (NO) is a unique and nearly ubiquitous molecule that is widely utilized as a signaling molecule in cells throughout the body. NO is highly diffusible, labile, and multiply reactive, suiting it well for its role as an important regulator of a number of diverse biologic processes, including vascular tone and permeability, platelet adhesion, neurotransmission, and mitochondrial respiration. NO can protect cells against antioxidant injury, can inhibit leukocyte adhesion, and can participate in antimicrobial defense, but can also have deleterious effects, including inhibition of enzyme function, promotion of DNA damage, and activation of inflammatory processes. This molecule's chemistry dictates its biologic activity, which can be both direct and indirect. In addition, NO has bimodal effects in a number of cells, maintaining homeostasis at low doses, and participating in pathophysiology in others. Perturbation of NO regulation is involved in the most important and prevalent disease processes in critical care units, including sepsis, acute lung injury, and multiple organ failure. Given that NO is ubiquitous, highly diffusible, and promiscuously reactive, its regulation is complex. The NO concentration, kinetics, and localization, both inside and outside the cell, are clearly crucial factors. In the present update we review a selection of studies that have yielded important information on these complex but important issues. Interpretation of these and other studies aimed at elucidating physiologic and pathophysiologic roles of NO must take this complexity into account. A full review of the role of NO in these diseases is beyond the scope of the current manuscript; the present article will focus on recent advances in understanding the complex role of NO in health and disease.
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Affiliation(s)
- Steven M Hollenberg
- Division of Critical Care Medicine, Cooper University Hospital, One Cooper Plaza, 366 Dorrance, Camden, NJ 08103, USA.
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34
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Experimental chemotherapy against Trypanosoma cruzi infection using ruthenium nitric oxide donors. Antimicrob Agents Chemother 2009; 53:4414-21. [PMID: 19581464 DOI: 10.1128/aac.00104-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ruthenium NO donors of the group trans-[Ru(NO)(NH3)4L]n+, where the ligand (L) is N-heterocyclic H2O, SO(3)(2-), or triethyl phosphite, are able to lyse Trypanosoma cruzi in vitro and in vivo. Using half-maximal (50%) inhibitory concentrations against bloodstream trypomastigotes (IC50try) and cytotoxicity data on mammalian V-79 cells (IC50V79), the in vitro therapeutic indices (TIs) (IC50V79/IC50try) for these compounds were calculated. Compounds that exhibited an in vitro TI of > or = 10 and trypanocidal activity against both epimastigotes and trypomastigotes with an IC50(try/epi) of < or = 100 microM were assayed in a mouse model for acute Chagas' disease, using two different routes (intraperitoneal and oral) for drug administration. A dose-effect relationship was observed, and from that, the ideal dose of 400 nmol/kg of body weight for both trans-[Ru(NO)(NH3)4isn](BF4)3 (isn, isonicotinamide) and trans-[Ru(NO)(NH3)4imN](BF4)3 (imN, imidazole) and median (50%) effective doses (ED50) of 86 and 190 nmol/kg, respectively, were then calculated. Since the 50% lethal doses (LD50) for both compounds are higher than 125 micromol/kg, the in vivo TIs (LD50/ED50) of the compounds are 1,453 for trans-[Ru(NO)(NH3)4isn](BF4)3 and 658 for trans-[Ru(NO)(NH3)4imN](BF4)3. Although these compounds exhibit a marked trypanocidal activity and are able to react with cysteine, they exhibit very low activity in T. cruzi-glycosomal glyceraldehyde-3-phosphate dehydrogenase tests, suggesting that this enzyme is not their target. The trans-[Ru(NO)(NH3)4isn](BF4)3 and trans-[Ru(NO)(NH3)4imN](BF4)3 compounds are able to eliminate amastigote nests in myocardium tissue at 400-nmol/kg doses and ensure the survival of all infected mice, thus opening a novel set of therapies to try against trypanosomatids.
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35
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Lu XM, Zhang GX, Yu YQ, Kimura S, Nishiyama A, Matsuyoshi H, Shimizu J, Takaki M. The opposite roles of nNOS in cardiac ischemia-reperfusion-induced injury and in ischemia preconditioning-induced cardioprotection in mice. J Physiol Sci 2009; 59:253-62. [PMID: 19340535 PMCID: PMC10717319 DOI: 10.1007/s12576-009-0030-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 02/05/2009] [Indexed: 01/28/2023]
Abstract
The role of neuronal nitric oxide synthase (nNOS) in cardiac ischemia-reperfusion (IR) and ischemia preconditioning (IP) is still controversial. Here, we focused on the possible roles of nNOS in cardiac IR and IP. Wild type C57BL/6 (WT) mice were subjected to coronary artery occlusion for 30 min followed by 24-h reperfusion (IR). Cardiac injury (infarct size and apoptotic cell number) was increased, associated with elevation of oxidative stress (lipid peroxidation) and nitrative stress (nitrotyrosine formation). A potent nNOS inhibitor, L-VNIO, and a superoxide dismutase mimetic and peroxynitrite scavenger, MnTBAP, significantly reduced IR-induced increases of oxidative/nitrative stress and cardiac injury. IR-induced cardiac injury in nNOS(-/-) (KO) mice was significantly lower than that in WT mice. MnTBAP markedly reduced IR-induced cardiac injury by suppression of oxidative/nitrative stress in KO mice. Cardiac IP was performed by three cycles of 5-min IR before 30-min ischemia followed by 24-h reperfusion. IP attenuated IR-induced cardiac injury in WT mice associated with reductions of oxidative/nitrative stress. IP-induced reduction of cardiac injury and oxidative/nitrative stress were eliminated by pretreatment with L-VNIO. In contrast with WT mice, IP had no protective effects in nNOS KO mice. In conclusion, nNOS played a dual role during cardiac IR and IP; nNOS exacerbated IR-induced injury by increasing oxidative/nitrative stress and contributed to IP-induced protection by inhibition of oxidative/nitrative stress.
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Affiliation(s)
- Xiao-Mei Lu
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Takamatsu 761-0793, Japan
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Protective effect of salidroside against H2O2-induced cell apoptosis in primary culture of rat hippocampal neurons. Mol Cell Biochem 2009; 332:85-93. [PMID: 19554425 DOI: 10.1007/s11010-009-0177-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Accepted: 06/09/2009] [Indexed: 10/20/2022]
Abstract
Salidroside, a phenylpropanoid glycoside separated from a medicinal plant Rhodiola rosea, has been documented to have protective effects on neuronal cells in vitro. This study investigated whether salidroside was able to extend its unique neuroprotection to primary cultured rat hippocampal neurons against hydrogen peroxide (H(2)O(2))-induced cell damage. Cell viability tests and cell apoptosis assays confirmed that salidroside pretreatment attenuated H(2)O(2)-stimulated apoptotic cell death in primary culture of hippocampal neurons in a concentration-dependent manner. The measurements of caspase-3 activity, nitric oxide (NO) production, and NO synthase (NOS) activity suggest that the protection of salidroside, shown in this study, might be mediated by inhibiting caspase-3 activity, and antagonizing NO production and NOS activity during H(2)O(2) stimulation. Perhaps, this study might contribute to the development of salidroside as a broad-spectrum agent for preventing and/or treating neuronal damage in neurodegenerative disorders.
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Slyvka Y, Inman SR, Malgor R, Jackson EJ, Yee J, Oshogwemoh O, Adame J, Nowak FV. Protective effects of antioxidant-fortified diet on renal function and metabolic profile in obese Zucker rat. Endocrine 2009; 35:89-100. [PMID: 19051067 PMCID: PMC2782430 DOI: 10.1007/s12020-008-9121-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 09/29/2008] [Accepted: 10/10/2008] [Indexed: 02/07/2023]
Abstract
Oxidative stress contributes to the pathophysiology of type 2 diabetes mellitus and its complications, including nephropathy. The current study was designed to test the hypothesis that a diet fortified with antioxidants would be beneficial to delay or prevent the progression of this disease. Male and female Zucker fa/fa rats were fed a control or an antioxidant (AO)-fortified diet starting at 4 weeks of age. Metabolic parameters, renal function, and renal histopathology were analyzed at 6, 13, and 20 weeks of age. Females on the AO diet had significantly lower blood glucose at 6 and 13 weeks, less severe renal pathology at 20 weeks, and higher glomerular filtration rates (GFR) at 20 weeks than age-matched females on the regular diet (P < 0.05). Metabolic parameters including blood glucose, insulin resistance, and serum cholesterol, and mean arterial pressure (MAP), worsened with age in both males and females, as expected. GFR decreased and renal pathology also became more severe with age. Finally, females on the AO diet had higher GFRs and lower MAP at 20 weeks than males on the same diet. This may denote a protective effect of the AO diet in females, but not in males. These findings may have implications for the role of antioxidants as therapy in humans with T2DM.
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Affiliation(s)
- Yuriy Slyvka
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
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38
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Zhang GX, Kimura S, Murao K, Shimizu J, Matsuyoshi H, Takaki M. Role of neuronal NO synthase in regulating vascular superoxide levels and mitogen-activated protein kinase phosphorylation. Cardiovasc Res 2008; 81:389-99. [DOI: 10.1093/cvr/cvn304] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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39
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Nitric oxide signaling and the regulation of myocardial function. J Mol Cell Cardiol 2008; 45:625-32. [PMID: 18722380 DOI: 10.1016/j.yjmcc.2008.07.015] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 06/12/2008] [Accepted: 07/17/2008] [Indexed: 12/25/2022]
Abstract
Nitric oxide, which is produced endogenously within cardiac myocytes by three distinct isoforms of nitric oxide synthase, is a key regulator of myocardial function. This review will focus on the regulation of myocardial function by each nitric oxide synthase isoform during health and disease, with a specific emphasis on the proposed end-targets and signaling pathways.
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Chen CA, Druhan LJ, Varadharaj S, Chen YR, Zweier JL. Phosphorylation of endothelial nitric-oxide synthase regulates superoxide generation from the enzyme. J Biol Chem 2008; 283:27038-47. [PMID: 18622039 DOI: 10.1074/jbc.m802269200] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the vasculature, nitric oxide (NO) is generated by endothelial NO synthase (eNOS) in a calcium/calmodulin-dependent reaction. With oxidative stress, the critical cofactor BH(4) is depleted, and NADPH oxidation is uncoupled from NO generation, leading to production of (O(2)*). Although phosphorylation of eNOS regulates in vivo NO generation, the effects of phosphorylation on eNOS coupling and O(2)* generation are unknown. Therefore, we phosphorylated recombinant BH(4)-free eNOS in vitro using native kinases and determined O(2)* generation using EPR spin trapping. Phosphorylation of Ser-1177 by Akt led to an increase (>50%) in maximal O(2)* generation from eNOS. Moreover, Ser-1177 phosphorylation greatly altered the Ca(2+) sensitivity of eNOS, such that O(2)* generation became largely Ca(2+)-independent. In contrast, phosphorylation of eNOS at Thr-495 by protein kinase Calpha (PKCalpha) had no effect on maximum activity or calcium sensitivity but decreased calmodulin binding and increased association with caveolin. In endothelial cells, eNOS-dependent O(2)* generation was stimulated by vascular endothelial growth factor that induced phosphorylation of Ser-1177. With PKC activation that led to phosphorylation of Thr-495, no inhibition of O(2)* generation occurred. As such, phosphorylation of eNOS at Ser-1177 is pivotal in the direct regulation of O(2)* and NO generation, altering both the Ca(2+) sensitivity of the enzyme and rate of product formation, whereas phosphorylation of Thr-495 indirectly affects this process through regulation of the calmodulin and caveolin interaction. Thus, Akt-mediated phosphorylation modulates eNOS uncoupling and greatly increases O(2)* generation from the enzyme at low Ca(2+) concentrations, and PKCalpha-mediated phosphorylation alters the sensitivity of the enzyme to other negative regulatory signals.
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Affiliation(s)
- Chun-An Chen
- Davis Heart and Lung Research Institute, Columbus, Ohio 43210, USA
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