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Eichwald T, da Silva LDB, Staats Pires AC, Niero L, Schnorrenberger E, Filho CC, Espíndola G, Huang WL, Guillemin GJ, Abdenur JE, Latini A. Tetrahydrobiopterin: Beyond Its Traditional Role as a Cofactor. Antioxidants (Basel) 2023; 12:1037. [PMID: 37237903 PMCID: PMC10215290 DOI: 10.3390/antiox12051037] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/19/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Tetrahydrobiopterin (BH4) is an endogenous cofactor for some enzymatic conversions of essential biomolecules, including nitric oxide, and monoamine neurotransmitters, and for the metabolism of phenylalanine and lipid esters. Over the last decade, BH4 metabolism has emerged as a promising metabolic target for negatively modulating toxic pathways that may result in cell death. Strong preclinical evidence has shown that BH4 metabolism has multiple biological roles beyond its traditional cofactor activity. We have shown that BH4 supports essential pathways, e.g., to generate energy, to enhance the antioxidant resistance of cells against stressful conditions, and to protect from sustained inflammation, among others. Therefore, BH4 should not be understood solely as an enzyme cofactor, but should instead be depicted as a cytoprotective pathway that is finely regulated by the interaction of three different metabolic pathways, thus assuring specific intracellular concentrations. Here, we bring state-of-the-art information about the dependency of mitochondrial activity upon the availability of BH4, as well as the cytoprotective pathways that are enhanced after BH4 exposure. We also bring evidence about the potential use of BH4 as a new pharmacological option for diseases in which mitochondrial disfunction has been implicated, including chronic metabolic disorders, neurodegenerative diseases, and primary mitochondriopathies.
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Affiliation(s)
- Tuany Eichwald
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
- Laboratory for Energy Metabolism, Division of Metabolic Disorders, CHOC Children’s Hospital, Orange, CA 92868, USA; (W.-L.H.); (J.E.A.)
| | - Lucila de Bortoli da Silva
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
| | - Ananda Christina Staats Pires
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
- Neuroinflammation Group, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Laís Niero
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
| | - Erick Schnorrenberger
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
| | - Clovis Colpani Filho
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
| | - Gisele Espíndola
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
- Neuroinflammation Group, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Wei-Lin Huang
- Laboratory for Energy Metabolism, Division of Metabolic Disorders, CHOC Children’s Hospital, Orange, CA 92868, USA; (W.-L.H.); (J.E.A.)
| | - Gilles J. Guillemin
- Neuroinflammation Group, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - José E. Abdenur
- Laboratory for Energy Metabolism, Division of Metabolic Disorders, CHOC Children’s Hospital, Orange, CA 92868, USA; (W.-L.H.); (J.E.A.)
| | - Alexandra Latini
- Laboratório de Bioenergética e Estresse Oxidativo—LABOX, Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88037-100, SC, Brazil; (T.E.); (L.N.); (C.C.F.); (G.E.)
- Laboratory for Energy Metabolism, Division of Metabolic Disorders, CHOC Children’s Hospital, Orange, CA 92868, USA; (W.-L.H.); (J.E.A.)
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Cincotta AH, Cersosimo E, Alatrach M, Ezrokhi M, Agyin C, Adams J, Chilton R, Triplitt C, Chamarthi B, Cominos N, DeFronzo RA. Bromocriptine-QR Therapy Reduces Sympathetic Tone and Ameliorates a Pro-Oxidative/Pro-Inflammatory Phenotype in Peripheral Blood Mononuclear Cells and Plasma of Type 2 Diabetes Subjects. Int J Mol Sci 2022; 23:ijms23168851. [PMID: 36012132 PMCID: PMC9407769 DOI: 10.3390/ijms23168851] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
Bromocriptine-QR is a sympatholytic dopamine D2 agonist for the treatment of type 2 diabetes that has demonstrated rapid (within 1 year) substantial reductions in adverse cardiovascular events in this population by as yet incompletely delineated mechanisms. However, a chronic state of elevated sympathetic nervous system activity and central hypodopaminergic function has been demonstrated to potentiate an immune system pro-oxidative/pro-inflammatory condition and this immune phenotype is known to contribute significantly to the advancement of cardiovascular disease (CVD). Therefore, the possibility exists that bromocriptine-QR therapy may reduce adverse cardiovascular events in type 2 diabetes subjects via attenuation of this underlying chronic pro-oxidative/pro-inflammatory state. The present study was undertaken to assess the impact of bromocriptine-QR on a wide range of immune pro-oxidative/pro-inflammatory biochemical pathways and genes known to be operative in the genesis and progression of CVD. Inflammatory peripheral blood mononuclear cell biology is both a significant contributor to cardiovascular disease and also a marker of the body’s systemic pro-inflammatory status. Therefore, this study investigated the effects of 4-month circadian-timed (within 2 h of waking in the morning) bromocriptine-QR therapy (3.2 mg/day) in type 2 diabetes subjects whose glycemia was not optimally controlled on the glucagon-like peptide 1 receptor agonist on (i) gene expression status (via qPCR) of a wide array of mononuclear cell pro-oxidative/pro-inflammatory genes known to participate in the genesis and progression of CVD (OXR1, NRF2, NQO1, SOD1, SOD2, CAT, GSR, GPX1, GPX4, GCH1, HMOX1, BiP, EIF2α, ATF4, PERK, XBP1, ATF6, CHOP, GSK3β, NFkB, TXNIP, PIN1, BECN1, TLR2, TLR4, TLR10, MAPK8, NLRP3, CCR2, GCR, L-selectin, VCAM1, ICAM1) and (ii) humoral measures of sympathetic tone (norepinephrine and normetanephrine), whole-body oxidative stress (nitrotyrosine, TBARS), and pro-inflammatory factors (IL-1β, IL-6, IL-18, MCP-1, prolactin, C-reactive protein [CRP]). Relative to pre-treatment status, 4 months of bromocriptine-QR therapy resulted in significant reductions of mRNA levels in PBMC endoplasmic reticulum stress-unfolded protein response effectors [GRP78/BiP (34%), EIF2α (32%), ATF4 (29%), XBP1 (25%), PIN1 (14%), BECN1 (23%)], oxidative stress response proteins [OXR1 (31%), NRF2 (32%), NQO1 (39%), SOD1 (52%), CAT (26%), GPX1 (33%), GPX4 (31%), GCH1 (30%), HMOX1 (40%)], mRNA levels of TLR pro-inflammatory pathway proteins [TLR2 (46%), TLR4 (20%), GSK3β (19%), NFkB (33%), TXNIP (18%), NLRP3 (32%), CCR2 (24%), GCR (28%)], mRNA levels of pro-inflammatory cellular receptor proteins CCR2 and GCR by 24% and 28%, and adhesion molecule proteins L-selectin (35%) and VCAM1 (24%). Relative to baseline, bromocriptine-QR therapy also significantly reduced plasma levels of norepinephrine and normetanephrine by 33% and 22%, respectively, plasma pro-oxidative markers nitrotyrosine and TBARS by 13% and 10%, respectively, and pro-inflammatory factors IL-18, MCP1, IL-1β, prolactin, and CRP by 21%,13%, 12%, 42%, and 45%, respectively. These findings suggest a unique role for circadian-timed bromocriptine-QR sympatholytic dopamine agonist therapy in reducing systemic low-grade sterile inflammation to thereby reduce cardiovascular disease risk.
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Affiliation(s)
- Anthony H. Cincotta
- VeroScience LLC, Tiverton, RI 02878, USA
- Correspondence: ; Tel.: +1-401-816-0525
| | - Eugenio Cersosimo
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Mariam Alatrach
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | | | - Christina Agyin
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - John Adams
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Robert Chilton
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Curtis Triplitt
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | | | | | - Ralph A. DeFronzo
- Texas Diabetes Institute, University Health System, San Antonio, TX 78207, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Vasquez-Vivar J, Shi Z, Tan S. Tetrahydrobiopterin in Cell Function and Death Mechanisms. Antioxid Redox Signal 2022; 37:171-183. [PMID: 34806400 PMCID: PMC9293684 DOI: 10.1089/ars.2021.0136] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/12/2021] [Accepted: 11/13/2021] [Indexed: 01/07/2023]
Abstract
Significance: Tetrahydrobiopterin (BH4) is most well known as a required cofactor for enzymes regulating cellular redox homeostasis, aromatic amino acid metabolism, and neurotransmitter synthesis. Less well known are the effects dependent on the cofactor's availability, factors governing its synthesis and recycling, redox implications of the cofactor itself, and protein-protein interactions that underlie cell death. This review provides an understanding of the recent advances implicating BH4 in the mechanisms of cell death and suggestions of possible therapeutic interventions. Recent Advances: The levels of BH4 often reflect the sum of synthetic and recycling enzyme activities. Enhanced expression of GTP cyclohydrolase, the rate-limiting enzyme in biosynthesis, increases BH4, leading to improved cell function and survival. Pharmacologically increasing BH4 levels has similar beneficial effects, leading to enhanced production of neurotransmitters and nitric oxide or reducing oxidant levels. The GTP cyclohydrolase-BH4 pairing has been implicated in a type of cell death, ferroptosis. At the cellular level, BH4 counteracts anticancer therapies directed to enhance ferroptosis via glutathione peroxidase 4 (GPX4) activity inhibition. Critical Issues: Because of the multitude of intertwined mechanisms, a clear relationship between BH4 and cell death is not well understood yet. The possibility that the cofactor directly influences cell viability has not been excluded in previous studies when modulating BH4-producing enzymes. Future Directions: The importance of cellular BH4 variations and BH4 biosynthetic enzymes to cell function and viability makes it essential to better characterize temporal changes, cofactor activity, and the influence on redox status, which in turn would help develop novel therapies. Antioxid. Redox Signal. 37, 171-183.
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Affiliation(s)
- Jeannette Vasquez-Vivar
- Redox Biology Program, Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Zhongjie Shi
- Department of Pediatrics, Wayne State University, Detroit, Michigan, USA
| | - Sidhartha Tan
- Department of Pediatrics, Wayne State University, Detroit, Michigan, USA
- Division of Neonatology, Children's Hospital of Michigan, Wayne State University and Central Michigan University, Detroit, Michigan, USA
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Feng Y, Feng Y, Gu L, Liu P, Cao J, Zhang S. The Critical Role of Tetrahydrobiopterin (BH4) Metabolism in Modulating Radiosensitivity: BH4/NOS Axis as an Angel or a Devil. Front Oncol 2021; 11:720632. [PMID: 34513700 PMCID: PMC8429800 DOI: 10.3389/fonc.2021.720632] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/12/2021] [Indexed: 12/16/2022] Open
Abstract
Ionizing radiation and radioactive materials have been widely used in industry, medicine, science and military. The efficacy of radiotherapy and adverse effects of normal tissues are closed related to cellular radiosensitivity. Molecular mechanisms underlying radiosensitivity are of significance to tumor cell radiosensitization as well as normal tissue radioprotection. 5,6,7,8-Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthases (NOS) and aromatic amino acid hydroxylases, and its biosynthesis involves de novo biosynthesis and a pterin salvage pathway. In this review we overview the role of BH4 metabolism in modulating radiosensitivity. BH4 homeostasis determines the role of NOS, affecting the production of nitric oxide (NO) and oxygen free radicals. Under conditions of oxidative stress, such as UV-radiation and ionizing radiation, BH4 availability is diminished due to its oxidation, which subsequently leads to NOS uncoupling and generation of highly oxidative free radicals. On the other hand, BH4/NOS axis facilitates vascular normalization, a process by which antiangiogenic therapy corrects structural and functional flaws of tumor blood vessels, which enhances radiotherapy efficacy. Therefore, BH4/NOS axis may serve as an angel or a devil in regulating cellular radiosensitivity. Finally, we will address future perspectives, not only from the standpoint of perceived advances in treatment, but also from the potential mechanisms. These advances have demonstrated that it is possible to modulate cellular radiosensitivity through BH4 metabolism.
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Affiliation(s)
- Yang Feng
- School of Radiation Medicine and Protection, State Key Laboratory of Radiation Medicine, Soochow University, Suzhou, China
| | - Yahui Feng
- China National Nuclear Corporation 416 Hospital (Second Affiliated Hospital of Chengdu Medical College), Chengdu, China
| | - Liming Gu
- School of Radiation Medicine and Protection, State Key Laboratory of Radiation Medicine, Soochow University, Suzhou, China
| | - Pengfei Liu
- School of Radiation Medicine and Protection, State Key Laboratory of Radiation Medicine, Soochow University, Suzhou, China
| | - Jianping Cao
- School of Radiation Medicine and Protection, State Key Laboratory of Radiation Medicine, Soochow University, Suzhou, China
| | - Shuyu Zhang
- China National Nuclear Corporation 416 Hospital (Second Affiliated Hospital of Chengdu Medical College), Chengdu, China.,West China Second University Hospital, Sichuan University, Chengdu, China.,West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
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Ezrokhi M, Zhang Y, Luo S, Cincotta AH. Time-of-Day-Dependent Effects of Bromocriptine to Ameliorate Vascular Pathology and Metabolic Syndrome in SHR Rats Held on High Fat Diet. Int J Mol Sci 2021; 22:ijms22116142. [PMID: 34200262 PMCID: PMC8201259 DOI: 10.3390/ijms22116142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 12/31/2022] Open
Abstract
The treatment of type 2 diabetes patients with bromocriptine-QR, a unique, quick release micronized formulation of bromocriptine, improves glycemic control and reduces adverse cardiovascular events. While the improvement of glycemic control is largely the result of improved postprandial hepatic glucose metabolism and insulin action, the mechanisms underlying the drug's cardioprotective effects are less well defined. Bromocriptine is a sympatholytic dopamine agonist and reduces the elevated sympathetic tone, characteristic of metabolic syndrome and type 2 diabetes, which potentiates elevations of vascular oxidative/nitrosative stress, known to precipitate cardiovascular disease. Therefore, this study investigated the impact of bromocriptine treatment upon biomarkers of vascular oxidative/nitrosative stress (including the pro-oxidative/nitrosative stress enzymes of NADPH oxidase 4, inducible nitric oxide (iNOS), uncoupled endothelial nitric oxide synthase (eNOS), the pro-inflammatory/pro-oxidative marker GTP cyclohydrolase 1 (GTPCH 1), and the pro-vascular health enzyme, soluble guanylate cyclase (sGC) as well as the plasma level of thiobarbituric acid reactive substances (TBARS), a circulating marker of systemic oxidative stress), in hypertensive SHR rats held on a high fat diet to induce metabolic syndrome. Inasmuch as the central nervous system (CNS) dopaminergic activities both regulate and are regulated by CNS circadian pacemaker circuitry, this study also investigated the time-of-day-dependent effects of bromocriptine treatment (10 mg/kg/day at either 13 or 19 h after the onset of light (at the natural waking time or late during the activity period, respectively) among animals held on 14 h daily photoperiods for 16 days upon such vascular biomarkers of vascular redox state, several metabolic syndrome parameters, and mediobasal hypothalamic (MBH) mRNA expression levels of neuropeptides neuropeptide Y (NPY) and agouti-related protein (AgRP) which regulate the peripheral fuel metabolism and of mRNA expression of other MBH glial and neuronal cell genes that support such metabolism regulating neurons in this model system. Such bromocriptine treatment at ZT 13 improved (reduced) biomarkers of vascular oxidative/nitrosative stress including plasma TBARS level, aortic NADPH oxidase 4, iNOS and GTPCH 1 levels, and improved other markers of coupled eNOS function, including increased sGC protein level, relative to controls. However, bromocriptine treatment at ZT 19 produced no improvement in either coupled eNOS function or sGC protein level. Moreover, such ZT 13 bromocriptine treatment reduced several metabolic syndrome parameters including fasting insulin and leptin levels, as well as elevated systolic and diastolic blood pressure, insulin resistance, body fat store levels and liver fat content, however, such effects of ZT 19 bromocriptine treatment were largely absent versus control. Finally, ZT 13 bromocriptine treatment reduced MBH NPY and AgRP mRNA levels and mRNA levels of several MBH glial cell/neuronal genes that code for neuronal support/plasticity proteins (suggesting a shift in neuronal structure/function to a new metabolic control state) while ZT 19 treatment reduced only AgRP, not NPY, and was with very little effect on such MBH glial cell genes expression. These findings indicate that circadian-timed bromocriptine administration at the natural circadian peak of CNS dopaminergic activity (that is diminished in insulin resistant states), but not outside this daily time window when such CNS dopaminergic activity is naturally low, produces widespread improvements in biomarkers of vascular oxidative stress that are associated with the amelioration of metabolic syndrome and reductions in MBH neuropeptides and gene expressions known to facilitate metabolic syndrome. These results of such circadian-timed bromocriptine treatment upon vascular pathology provide potential mechanisms for the observed marked reductions in adverse cardiovascular events with circadian-timed bromocriptine-QR therapy (similarly timed to the onset of daily waking as in this study) of type 2 diabetes subjects and warrant further investigations into related mechanisms and the potential application of such intervention to prediabetes and metabolic syndrome patients as well.
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Bil P, Ciesielska S, Jaksik R, Rzeszowska-Wolny J. Circuits Regulating Superoxide and Nitric Oxide Production and Neutralization in Different Cell Types: Expression of Participating Genes and Changes Induced by Ionizing Radiation. Antioxidants (Basel) 2020; 9:antiox9080701. [PMID: 32756515 PMCID: PMC7463469 DOI: 10.3390/antiox9080701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/22/2020] [Accepted: 07/29/2020] [Indexed: 12/21/2022] Open
Abstract
Superoxide radicals, together with nitric oxide (NO), determine the oxidative status of cells, which use different pathways to control their levels in response to stressing conditions. Using gene expression data available in the Cancer Cell Line Encyclopedia and microarray results, we compared the expression of genes engaged in pathways controlling reactive oxygen species and NO production, neutralization, and changes in response to the exposure of cells to ionizing radiation (IR) in human cancer cell lines originating from different tissues. The expression of NADPH oxidases and NO synthases that participate in superoxide radical and NO production was low in all cell types. Superoxide dismutase, glutathione peroxidase, thioredoxin, and peroxiredoxins participating in radical neutralization showed high expression in nearly all cell types. Some enzymes that may indirectly influence superoxide radical and NO levels showed tissue-specific expression and differences in response to IR. Using fluorescence microscopy and specific dyes, we followed the levels and the distribution of superoxide and NO radicals in living melanoma cells at different times after exposure to IR. Directly after irradiation, we observed an increase of superoxide radicals and NO coexistent in the same subcellular locations, suggesting a switch of NO synthase to the production of superoxide radicals.
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Affiliation(s)
- Patryk Bil
- Department of Systems Biology and Engineering, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, 44-100 Gliwice, Poland; (P.B.); (S.C.); (R.J.)
- Biotechnology Centre, Silesian University of Technology, 44-100 Gliwice, Poland
| | - Sylwia Ciesielska
- Department of Systems Biology and Engineering, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, 44-100 Gliwice, Poland; (P.B.); (S.C.); (R.J.)
- Biotechnology Centre, Silesian University of Technology, 44-100 Gliwice, Poland
| | - Roman Jaksik
- Department of Systems Biology and Engineering, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, 44-100 Gliwice, Poland; (P.B.); (S.C.); (R.J.)
| | - Joanna Rzeszowska-Wolny
- Department of Systems Biology and Engineering, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, 44-100 Gliwice, Poland; (P.B.); (S.C.); (R.J.)
- Biotechnology Centre, Silesian University of Technology, 44-100 Gliwice, Poland
- Correspondence:
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Baxter-Parker G, Prebble HM, Cross S, Steyn N, Shchepetkina A, Hock BD, Cousins A, Gieseg SP. Neopterin formation through radical scavenging of superoxide by the macrophage synthesised antioxidant 7,8-dihydroneopterin. Free Radic Biol Med 2020; 152:142-151. [PMID: 32145301 DOI: 10.1016/j.freeradbiomed.2020.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/26/2020] [Accepted: 03/02/2020] [Indexed: 12/15/2022]
Abstract
Clinical measurement of neopterin has been extensively used as a marker of inflammation but the in vivo mechanism generating neopterin is poorly understood. Neopterin is described as the oxidation product of 7,8-dihydroneopterin, a potent antioxidant generated by monocyte/macrophages in response to interferon-γ. While peroxyl and hydroxyl scavenging generates dihydroxanthopterin, hypochlorite efficiently oxidises 7,8-dihydroneopterin into neopterin, but this reaction alone does not explain the high levels of neopterin seen in clinical data. Here, we examine whether superoxide scavenging by 7,8-dihydroneopterin generates neopterin. U937 cells incubated with oxLDL showed a time dependent increase superoxide and 7,8-dihydroneopterin oxidation to neopterin. Neopterin generation in oxLDL or phorbol ester treated U937 cells or human monocytes was inhibited by apocynin and PEG-SOD. Addition of the myeloperoxidase inhibitor 4-aminobenzoic acid hydrazide (ABAH) had no effect of the superoxide generation or neopterin formation. 7,8-Dihydroneopterin reacted with superoxide/hydroxy radical mixtures generated by X-ray radiolysis to give neopterin. Formation of neopterin by superoxide derived from the xanthine/xanthine oxidase system was inhibited by superoxide dismutase. Neopterin formation was inhibited by apocynin in phorbol ester treated human carotid plaque rings in tissue culture. These results indicate that 7,8-dihydroneopterin scavenges superoxide and is subsequently oxidised into neopterin in cellular and cell-free experimental systems.
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Affiliation(s)
- Gregory Baxter-Parker
- Free Radical Biochemistry, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Hannah M Prebble
- Free Radical Biochemistry, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Sean Cross
- Free Radical Biochemistry, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Nina Steyn
- Free Radical Biochemistry, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Anastasia Shchepetkina
- Free Radical Biochemistry, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Barry D Hock
- Haematology Research, Department of Pathology and Biomedical Sciences, University of Otago Christchurch, New Zealand
| | - Andrew Cousins
- Department of Medical Physics and Bioengineering, Christchurch Hospital, Canterbury District Health Board, New Zealand
| | - Steven P Gieseg
- Free Radical Biochemistry, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand; Department of Radiology, University of Otago Christchurch, New Zealand; European Organization for Nuclear Research (CERN), Geneva, Switzerland.
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Murugesan T, Durairaj N, Ramasamy M, Jayaraman K, Palaniswamy M, Jayaraman A. Analeptic agent from microbes upon cyanide degradation. Appl Microbiol Biotechnol 2017; 102:1557-1565. [PMID: 29285551 DOI: 10.1007/s00253-017-8674-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/23/2017] [Accepted: 11/23/2017] [Indexed: 01/15/2023]
Abstract
Microbes being the initial form of life and ubiquitous in occurrence, they adapt to the environment quickly. The microbial metabolism undergoes alteration to ensure conducive environment either by degrading the toxic substances or producing toxins to protect themselves. The presence of cyanide waste triggers the cyanide degrading enzymes in the microbes which facilitate the microbes to utilize the cyanide for its growth. To enable the degradation of cyanide, the microbes also produce the necessary cofactors and enhancers catalyzing the degradation pathways. Pterin, a cofactor of the enzyme cyanide monooxygenase catalyzing the oxidation of cyanide, is considered to be a potentially bioactive compound. Besides that, the pterins also act as cofactor for the enzymes involved in neurotransmitter metabolism. The therapeutic values of pterin as neuromodulating agent validate the necessity to pursue the commercial production of pterin. Even though chemical synthesis is possible, the non-toxic methods of pterin production need to be given greater attention in future.
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Affiliation(s)
- Thandeeswaran Murugesan
- Cancer Therapeutics Laboratory, Department of Microbial Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | - Nisshanthini Durairaj
- Cancer Therapeutics Laboratory, Department of Microbial Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | - Mahendran Ramasamy
- Cancer Therapeutics Laboratory, Department of Microbial Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | - Karunya Jayaraman
- Cancer Therapeutics Laboratory, Department of Microbial Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | - Muthusamy Palaniswamy
- Department of Microbiology, Karpagam University, Coimbatore, Tamil Nadu, 641021, India
| | - Angayarkanni Jayaraman
- Cancer Therapeutics Laboratory, Department of Microbial Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India.
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Ghisoni K, Martins RDP, Barbeito L, Latini A. Neopterin as a potential cytoprotective brain molecule. J Psychiatr Res 2015; 71:134-9. [PMID: 26476490 DOI: 10.1016/j.jpsychires.2015.10.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/18/2015] [Accepted: 10/01/2015] [Indexed: 11/29/2022]
Abstract
Neopterin, a byproduct of the tetrahydrobiopterin de novo pathway, is found in increased levels in cerebrospinal fluid and plasma and significantly increases upon damage, infection or during immune system activation. The production of this compound seems almost restricted to the monocyte/macrophage linage cells, in response to interferon-γ stimulation. However, it is unclear whether and which nervous cells are able to synthesize neopterin, respond to any stressor applied extracellularly, or even the role of the compound in the central nervous system. Here we propose a potential cytoprotective role of neopterin in the brain, and show evidence that cultured rat astrocytes are responsive to the molecule; the pterin elicited increased hemeoxygenase-1 cellular content and decreased oxidative stress induced by mitochondrial dysfunction. Further studies are needed to clarify neopterin's cytoprotective effects in the central nervous system, and its potential role in different neuroinflammatory diseases.
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Affiliation(s)
- Karina Ghisoni
- Laboratório de Bioenergética e Estresse Oxidativo - LABOX, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Roberta de Paula Martins
- Laboratório de Bioenergética e Estresse Oxidativo - LABOX, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | | | - Alexandra Latini
- Laboratório de Bioenergética e Estresse Oxidativo - LABOX, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
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10
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Pathak R, Pawar SA, Fu Q, Gupta PK, Berbée M, Garg S, Sridharan V, Wang W, Biju PG, Krager KJ, Boerma M, Ghosh SP, Cheema AK, Hendrickson HP, Aykin-Burns N, Hauer-Jensen M. Characterization of transgenic Gfrp knock-in mice: implications for tetrahydrobiopterin in modulation of normal tissue radiation responses. Antioxid Redox Signal 2014; 20:1436-46. [PMID: 23521531 PMCID: PMC3936502 DOI: 10.1089/ars.2012.5025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 02/22/2013] [Accepted: 03/22/2013] [Indexed: 01/17/2023]
Abstract
AIMS The free radical scavenger and nitric oxide synthase cofactor, 5,6,7,8-tetrahydrobiopterin (BH4), plays a well-documented role in many disorders associated with oxidative stress, including normal tissue radiation responses. Radiation exposure is associated with decreased BH4 levels, while BH4 supplementation attenuates aspects of radiation toxicity. The endogenous synthesis of BH4 is catalyzed by the enzyme guanosine triphosphate cyclohydrolase I (GTPCH1), which is regulated by the inhibitory GTP cyclohydrolase I feedback regulatory protein (GFRP). We here report and characterize a novel, Cre-Lox-driven, transgenic mouse model that overexpresses Gfrp. RESULTS Compared to control littermates, transgenic mice exhibited high transgene copy numbers, increased Gfrp mRNA and GFRP expression, enhanced GFRP-GTPCH1 interaction, reduced BH4 levels, and low glutathione (GSH) levels and differential mitochondrial bioenergetic profiles. After exposure to total body irradiation, transgenic mice showed decreased BH4/7,8-dihydrobiopterin ratios, increased vascular oxidative stress, and reduced white blood cell counts compared with controls. INNOVATION AND CONCLUSION This novel Gfrp knock-in transgenic mouse model allows elucidation of the role of GFRP in the regulation of BH4 biosynthesis. This model is a valuable tool to study the involvement of BH4 in whole body and tissue-specific radiation responses and other conditions associated with oxidative stress.
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Affiliation(s)
- Rupak Pathak
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Snehalata A. Pawar
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Qiang Fu
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Prem K. Gupta
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Maaike Berbée
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Sarita Garg
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Vijayalakshmi Sridharan
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Wenze Wang
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Prabath G. Biju
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Kimberly J. Krager
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Marjan Boerma
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Sanchita P. Ghosh
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Amrita K. Cheema
- Department of Oncology, Georgetown University Medical Center, Washington, District of Columbia
| | - Howard P. Hendrickson
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nukhet Aykin-Burns
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Martin Hauer-Jensen
- Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Surgical Service, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas
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11
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Abstract
BH4 (6R-L-erythro-5,6,7,8-tetrahydrobiopterin) is an essential cofactor of a set of enzymes that are of central metabolic importance, including four aromatic amino acid hydroxylases, alkylglycerol mono-oxygenase and three NOS (NO synthase) isoenzymes. Consequently, BH4 is present in probably every cell or tissue of higher organisms and plays a key role in a number of biological processes and pathological states associated with monoamine neurotransmitter formation, cardiovascular and endothelial dysfunction, the immune response and pain sensitivity. BH4 is formed de novo from GTP via a sequence of three enzymatic steps carried out by GTP cyclohydrolase I, 6-pyruvoyltetrahydropterin synthase and sepiapterin reductase. An alternative or salvage pathway involves dihydrofolate reductase and may play an essential role in peripheral tissues. Cofactor regeneration requires pterin-4a-carbinolamine dehydratase and dihydropteridine reductase, except for NOSs, in which the BH4 cofactor undergoes a one-electron redox cycle without the need for additional regeneration enzymes. With regard to the regulation of cofactor biosynthesis, the major controlling point is GTP cyclohydrolase I. BH4 biosynthesis is controlled in mammals by hormones and cytokines. BH4 deficiency due to autosomal recessive mutations in all enzymes, except for sepiapterin reductase, has been described as a cause of hyperphenylalaninaemia. A major contributor to vascular dysfunction associated with hypertension, ischaemic reperfusion injury, diabetes and others, appears to be an effect of oxidized BH4, which leads to an increased formation of oxygen-derived radicals instead of NO by decoupled NOS. Furthermore, several neurological diseases have been suggested to be a consequence of restricted cofactor availability, and oral cofactor replacement therapy to stabilize mutant phenylalanine hydroxylase in the BH4-responsive type of hyperphenylalaninaemia has an advantageous effect on pathological phenylalanine levels in patients.
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Affiliation(s)
- Ernst R Werner
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck A-6020, Austria
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12
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Berbee M, Fu Q, Boerma M, Pathak R, Zhou D, Kumar KS, Hauer-Jensen M. Reduction of radiation-induced vascular nitrosative stress by the vitamin E analog γ-tocotrienol: evidence of a role for tetrahydrobiopterin. Int J Radiat Oncol Biol Phys 2011; 79:884-91. [PMID: 20950957 PMCID: PMC3023840 DOI: 10.1016/j.ijrobp.2010.08.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 08/19/2010] [Accepted: 08/20/2010] [Indexed: 01/13/2023]
Abstract
PURPOSE The vitamin E analog γ-tocotrienol (GT3) is a powerful radioprotector. GT3 reduces postradiation vascular peroxynitrite production, an effect dependent on inhibition of hydroxy-methylglutaryl-coenzyme A reductase. Hydroxy-methylglutaryl-coenzyme A reductase inhibitors mediate their pleiotropic effects via endothelial nitric oxide synthase that requires the cofactor tetrahydrobiopterin (BH4). This study investigated the effects of radiation on BH4 bioavailability and of GT3 on BH4 metabolism. METHODS AND MATERIALS Mice were exposed to 8.5 Gy of total body irradiation (TBI). Lung BH4 and total biopterin concentrations were measured 0, 3.5, 7, 14, and 21 days after TBI by use of differential oxidation followed by high-performance liquid chromatography. The effect of exogenous GT3 and BH4 treatment on postradiation vascular oxidative stress and bone marrow colony-forming units were assessed in vivo. The effect of GT3 on endothelial cell apoptosis and endothelial expression of guanosine triphosphate (GTP) cyclohydrolase 1 (GTPCH), GTPCH feedback regulatory protein (GFRP), GFRP transcription, GFRP protein levels, and GFRP-GTPCH protein binding was determined in vitro. RESULTS Compared with baseline levels, lung BH4 concentrations decreased by 24% at 3.5 days after TBI, an effect that was reversed by GT3. At 14 and 21 days after TBI, compensatory increases in BH4 (58% and 80%, respectively) were observed. Relative to vehicle-treated controls, both GT3 and BH4 supplementation reduced postirradiation vascular peroxynitrite production at 3.5 days (by 66% and 33%, respectively), and BH4 resulted in a 68% increase in bone marrow colony-forming units. GT3 ameliorated endothelial cell apoptosis and reduced endothelial GFRP protein levels and GFRP-GTPCH binding by decreasing transcription of the GFRP gene. CONCLUSIONS BH4 bioavailability is reduced in the early postradiation phase. Exogenous administration of BH4 reduces postirradiation vascular oxidative stress. GT3 potently reduces the expression of GFRP, one of the key regulatory proteins in the BH4 pathway, and may thus exert some of its beneficial effects on postradiation free radical production partly by counteracting the decrease in BH4.
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Affiliation(s)
- Maaike Berbee
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Qiang Fu
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Marjan Boerma
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Rupak Pathak
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - Daohong Zhou
- University of Arkansas for Medical Sciences, Little Rock, AR
| | - K. Sree Kumar
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD
| | - Martin Hauer-Jensen
- University of Arkansas for Medical Sciences, Little Rock, AR
- Central Arkansas Veterans Healthcare System, Little Rock, AR
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13
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Tatham AL, Crabtree MJ, Warrick N, Cai S, Alp NJ, Channon KM. GTP cyclohydrolase I expression, protein, and activity determine intracellular tetrahydrobiopterin levels, independent of GTP cyclohydrolase feedback regulatory protein expression. J Biol Chem 2009; 284:13660-13668. [PMID: 19286659 PMCID: PMC2679467 DOI: 10.1074/jbc.m807959200] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 03/10/2009] [Indexed: 11/06/2022] Open
Abstract
GTP cyclohydrolase I (GTPCH) is a key enzyme in the synthesis of tetrahydrobiopterin (BH4), a required cofactor for nitricoxide synthases and aromatic amino acid hydroxylases. Alterations of GTPCH activity and BH4 availability play an important role in human disease. GTPCH expression is regulated by inflammatory stimuli, in association with reduced expression of GTP cyclohydrolase feedback regulatory protein (GFRP). However, the relative importance of GTPCH expression versus GTPCH activity and the role of GFRP in relation to BH4 bioavailability remain uncertain. We investigated these relationships in a cell line with tet-regulated GTPCH expression and in the hph-1 mouse model of GTPCH deficiency. Doxycycline exposure resulted in a dose-dependent decrease in GTPCH protein and activity, with a strong correlation between GTPCH expression and BH4 levels (r(2) = 0.85, p < 0.0001). These changes in GTPCH and BH4 had no effect on GFRP expression or protein levels. GFRP overexpression and knockdown in tet-GCH cells did not alter GTPCH activity or BH4 levels, and GTPCH-specific knockdown in sEnd.1 endothelial cells had no effect on GFRP protein. In mouse liver we observed a graded reduction of GTPCH expression, protein, and activity, from wild type, heterozygote, to homozygote littermates, with a striking linear correlation between GTPCH expression and BH4 levels (r(2) = 0.82, p < 0.0001). Neither GFRP expression nor protein differed between wild type, heterozygote, nor homozygote mice, despite the substantial differences in BH4. We suggest that GTPCH expression is the primary regulator of BH4 levels, and changes in GTPCH or BH4 are not necessarily accompanied by changes in GFRP expression.
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Affiliation(s)
- Amy L Tatham
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom
| | - Mark J Crabtree
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom
| | - Nicholas Warrick
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom
| | - Shijie Cai
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom
| | - Nicholas J Alp
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom
| | - Keith M Channon
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, United Kingdom.
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Schmidt TS, Alp NJ. Mechanisms for the role of tetrahydrobiopterin in endothelial function and vascular disease. Clin Sci (Lond) 2007; 113:47-63. [PMID: 17555404 DOI: 10.1042/cs20070108] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
NO produced by eNOS (endothelial nitric oxide synthase) is a key mediator of vascular homoeostasis. NO bioavailability is reduced early in vascular disease states, such as hypercholesterolaemia, diabetes and hypertension, and throughout the progression of atherosclerosis. This is a result of both reduced NO synthesis and increased NO consumption by reactive oxygen species. eNOS enzymatic activity appears to be determined by the availability of its cofactor BH4 (tetrahydrobiopterin). When BH4 levels are adequate, eNOS produces NO; when BH4 levels are limiting, eNOS becomes enzymatically uncoupled and generates superoxide, contributing to vascular oxidative stress and endothelial dysfunction. BH4 bioavailability is determined by a balance of enzymatic de novo synthesis and recycling, versus oxidative degradation in dysfunctional endothelium. Augmenting vascular BH4 levels by pharmacological supplementation, by enhancing the rate of de novo biosynthesis or by measures to reduce BH4 oxidation have been shown in experimental studies to enhance NO bioavailability. Thus BH4 represents a potential therapeutic target for preserving eNOS function in vascular disease.
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Affiliation(s)
- Tim S Schmidt
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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